jamesh
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Pi 4/400/CM4 with 1366x768 display not working?

Tue Sep 08, 2020 9:19 am

Last edited by 6by9 on Fri Aug 06, 2021 12:58 pm, edited 1 time in total.
Reason: Update title to include 400 & CM4
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LTolledo
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Re: Pi 4 with 1366x768 display not working?

Tue Sep 08, 2020 1:12 pm

works like a charm! thanks!

now to test this on my old piTop case so I can upgrade it from RPi3B to RPi4B-2G

UPDATE:
my RPi4B-4G boots up with display on the old PiTop laptop case with resolution set to 1360 x 768

many thanks! :D :D :D
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steshell
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Re: Pi 4 with 1366x768 display not working?

Sun Nov 01, 2020 12:49 am

jamesh wrote:
Tue Sep 08, 2020 9:19 am
Please see here for more details.

https://www.raspberrypi.org/documentati ... i4-hdmi.md

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7F20
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Re: Pi 4 with 1366x768 display not working?

Fri Feb 05, 2021 6:28 pm

Would it work if you were, for example, creating an "hdmi_timings=" that contains 2 odd values, so that the line pixel count ends up being even?

Like, let's say both the front and the back porches had an odd value; that would make the line total even. Would that be okay, or does that still violate the condition of 2 pixels per cycle?

Thanks

6by9
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Re: Pi 4 with 1366x768 display not working?

Sun Feb 07, 2021 10:10 am

7F20 wrote:
Fri Feb 05, 2021 6:28 pm
Would it work if you were, for example, creating an "hdmi_timings=" that contains 2 odd values, so that the line pixel count ends up being even?

Like, let's say both the front and the back porches had an odd value; that would make the line total even. Would that be okay, or does that still violate the condition of 2 pixels per cycle?

Thanks
If you looked at the timings of 1366x768 then you'd see that the overall line length is even - 1792 pixels total. The sync pulse width is 143 pixels, and the back porch is 213 pixels.

Whilst you could produce sync of 144 and bp of 212 pixels, or 142 and 214 pixels, those are not the same mode, and there are some displays that object to those tweaks.
There is no way for the sync event to be signalled as being in the middle of the two pixels produced per cycle.
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7F20
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Re: Pi 4 with 1366x768 display not working?

Mon Feb 08, 2021 12:23 am

Thanks for your reply.

Sorry about the duplicate post.
6by9 wrote:
Sun Feb 07, 2021 10:10 am
There is no way for the sync event to be signalled as being in the middle of the two pixels produced per cycle.
I'm not sure if understand the behavior of the clock and it's relationship to each aspect of the modeline.

Since each individual part of the modeline has to be divisible by 2, does that mean that each part of the line is parsed separately?

And because it's drawing each little part separately, the sync pulses and porches are issued one after the other and must conform to an even number?

For some reason, I had just assumed that it would be drawing a whole line including the sync info and porches all at once or something.

Is there something I can read to understand better how this works?

Thanks

drtechno
Posts: 261
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Re: Pi 4 with 1366x768 display not working?

Mon May 03, 2021 8:26 pm

1366x768 is not an HDMI mode. It is a composite video clock mode. This is why they shouldn't remove all those setting for composite video in the firmware @jamesh. This is coming from a TV / AV repair guy (me).


UXVGA is close, but some TVs do not like to clock with anything above 65hz. Typically these monitors have the component video inputs (Pr-Pg-Pb) and no pin 14 and 19 connected.

So you will most likely have to force the hdmi to turn on, and run an xga mode (HDMI group 2 HDMI_DMT_1360x768_60 = 0x27 according to the mode list)

cspan
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Pi 400 too?

Tue May 11, 2021 10:40 pm

It may not be evident from the documentation page title, "Raspberry Pi 4 HDMI pipeline", but I found it necessary to employ this configuration edit to my Pi 400's config.txt file to get the ideal desktop fit for my 1366x768 resolution television.

Thanks for the troubleshooting sticky!

aBUGSworstnightmare
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Re: Pi 4/400/CM4 with 1366x768 display not working?

Sat Aug 07, 2021 6:51 am

viewtopic.php?f=44&t=305690&start=150#p1861870
Shown my results when testing a 1366x768pixel module on CM4. Tweaking the timing to 1364pixels solved the issue. I will post the hdmi_timing details in case somebody is interrested in.

cspan
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Re: Pi 400 too?

Sun Aug 08, 2021 12:28 am

cspan wrote:
Tue May 11, 2021 10:40 pm
It may not be evident from the documentation page title, "Raspberry Pi 4 HDMI pipeline", but I found it necessary to employ this configuration edit to my Pi 400's config.txt file to get the ideal desktop fit for my 1366x768 resolution television.

Thanks for the troubleshooting sticky!
Update: after playing around with trying to USB boot from a portable SSD, I went back to my microSD boot, only to find my 1366x768 television resolution was messed up. It was defaulting to 1920x1080 (which is beyond the TV's ability), so stuff was running off the screen. What's more perplexing is that even though the config.txt still had the changes I made (e.g., hdmi_cvt=1360 768 60 is the third line added), that choice was not available under the display configuration resolution choices! I think it was before, but now it's gone. In the order presented, the choices jump from 1280x720 to 1920x1080.

I also tried the CLI version of the raspi-config and the desired option isn't there either.

It worked before, so it's not like my TV isn't capable of it. I just want to get it back to where it was ... so I can then return to figuring out what's going wrong with the portable SSD. Right now, though, my Pi400 is in less of a state of optimal tuning than it was this morning. :(

Would love some help if anyone has ideas of what I can do to fix things.

BTW, this is all on the 64-bit beta RPiOS.

aBUGSworstnightmare
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Re: Pi 400 too?

Mon Aug 09, 2021 3:11 am

cspan wrote:
Sun Aug 08, 2021 12:28 am
cspan wrote:
Tue May 11, 2021 10:40 pm
It may not be evident from the documentation page title, "Raspberry Pi 4 HDMI pipeline", but I found it necessary to employ this configuration edit to my Pi 400's config.txt file to get the ideal desktop fit for my 1366x768 resolution television.

Thanks for the troubleshooting sticky!
BTW, this is all on the 64-bit beta RPiOS.
find the failure: 64bit BETA!

There might be other things than a resolution issue! What's in your config.txt? What is the result of

Code: Select all

xrandr --verbose

cspan
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Re: Pi 400 too?

Mon Aug 09, 2021 1:36 pm

aBUGSworstnightmare wrote:
Mon Aug 09, 2021 3:11 am
find the failure: 64bit BETA!
Well, it was working in 64-bit beta before. Perhaps some update broke functionality, because even though I edited config.txt to include the necessary verbiage (hdmi_group=2, hdmi_mode=87, hdmi_cvt=1360 768 60), that resolution no longer appears in the GUI application, Screen Configuration (I think that's the name of it ...). It also does not appear as an option in raspi-config (CLI).

I'm using the HDMI port closest to the USB-C power port.
aBUGSworstnightmare wrote:
Mon Aug 09, 2021 3:11 am
There might be other things than a resolution issue! What's in your config.txt? What is the result of

Code: Select all

xrandr --verbose
For config.txt, see above ... I just added the settings shown here ...
https://www.raspberrypi.org/documentati ... i-pipeline

though it's not clear to me what the difference is between editing in those values, or specifying hdmi_mode=39.
https://www.raspberrypi.org/documentati ... my-monitor

as for xrandr, quite a bit of output - here it is, running off microSD at 1280x720 (since 1360x768 isn't offered as a choice anymore).

Code: Select all

pi@pi400:~ $ xrandr --verbose
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 7680 x 7680
HDMI-1 disconnected primary (normal left inverted right x axis y axis)
	Identifier: 0x45
	Timestamp:  11573
	Subpixel:   unknown
	Clones:    
	CRTCs:      3
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	max bpc: 8 
		range: (8, 12)
	bottom margin: 48 
		range: (0, 100)
	top margin: 48 
		range: (0, 100)
	right margin: 48 
		range: (0, 100)
	left margin: 48 
		range: (0, 100)
	Colorspace: Default 
		supported: Default, SMPTE_170M_YCC, BT709_YCC, XVYCC_601, XVYCC_709, SYCC_601, opYCC_601, opRGB, BT2020_CYCC, BT2020_RGB, BT2020_YCC, DCI-P3_RGB_D65, DCI-P3_RGB_Theater
	link-status: Good 
		supported: Good, Bad
	CONNECTOR_ID: 32 
		supported: 32
	non-desktop: 0 
		range: (0, 1)
HDMI-2 connected 1280x720+0+0 (0x53) normal (normal left inverted right x axis y axis) 609mm x 347mm
	Identifier: 0x46
	Timestamp:  11573
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       4
	CRTCs:      4
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	EDID: 
		00ffffffffffff004c2d3c0c00000000
		2e180103804627780aee91a3544c9926
		0f5054bdee0081c00101010101010101
		010101010101662156aa51001e30468f
		3300615b2100001e011d007251d01e20
		6e285500615b2100001e000000fd0018
		4b0f4417000a202020202020000000fc
		0053414d53554e470a20202020200107
		020325f14d841305140312101f202122
		07162309070783010000e2000f67030c
		001000b82d011d80d0721c1620102c25
		80615b2100009e011d8018711c162058
		2c2500615b2100009e011d00bc52d01e
		20b8285540615b2100001e8c0ad09020
		4031200c405500615b210000188c0ad0
		8a20e02d10103e9600615b21000018f2
	max bpc: 8 
		range: (8, 12)
	bottom margin: 0 
		range: (0, 100)
	top margin: 0 
		range: (0, 100)
	right margin: 0 
		range: (0, 100)
	left margin: 0 
		range: (0, 100)
	Colorspace: Default 
		supported: Default, SMPTE_170M_YCC, BT709_YCC, XVYCC_601, XVYCC_709, SYCC_601, opYCC_601, opRGB, BT2020_CYCC, BT2020_RGB, BT2020_YCC, DCI-P3_RGB_D65, DCI-P3_RGB_Theater
	link-status: Good 
		supported: Good, Bad
	CONNECTOR_ID: 40 
		supported: 40
	non-desktop: 0 
		range: (0, 1)
  1920x1080 (0x48) 148.500MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  67.50KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  60.00Hz
  1920x1080 (0x49) 148.500MHz +HSync +VSync
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock  56.25KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  50.00Hz
  1920x1080 (0x4a) 148.352MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  67.43KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  59.94Hz
  1920x1080i (0x4b) 74.250MHz +HSync +VSync Interlace
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  33.75KHz
        v: height 1080 start 1084 end 1094 total 1125           clock  60.00Hz
  1920x1080i (0x4c) 74.250MHz +HSync +VSync Interlace
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock  28.12KHz
        v: height 1080 start 1084 end 1094 total 1125           clock  50.00Hz
  1920x1080 (0x4d) 74.250MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  33.75KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  30.00Hz
  1920x1080 (0x4e) 74.250MHz +HSync +VSync
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock  28.12KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  25.00Hz
  1920x1080 (0x4f) 74.250MHz +HSync +VSync
        h: width  1920 start 2558 end 2602 total 2750 skew    0 clock  27.00KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  24.00Hz
  1920x1080i (0x50) 74.176MHz +HSync +VSync Interlace
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  33.72KHz
        v: height 1080 start 1084 end 1094 total 1125           clock  59.94Hz
  1920x1080 (0x51) 74.176MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  33.72KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  29.97Hz
  1920x1080 (0x52) 74.176MHz +HSync +VSync
        h: width  1920 start 2558 end 2602 total 2750 skew    0 clock  26.97KHz
        v: height 1080 start 1084 end 1089 total 1125           clock  23.98Hz
  1280x720 (0x53) 74.250MHz +HSync +VSync *current
        h: width  1280 start 1390 end 1430 total 1650 skew    0 clock  45.00KHz
        v: height  720 start  725 end  730 total  750           clock  60.00Hz
  1280x720 (0x54) 74.250MHz +HSync +VSync
        h: width  1280 start 1720 end 1760 total 1980 skew    0 clock  37.50KHz
        v: height  720 start  725 end  730 total  750           clock  50.00Hz
  1280x720 (0x55) 74.176MHz +HSync +VSync
        h: width  1280 start 1390 end 1430 total 1650 skew    0 clock  44.96KHz
        v: height  720 start  725 end  730 total  750           clock  59.94Hz
  1024x768 (0x56) 78.750MHz +HSync +VSync
        h: width  1024 start 1040 end 1136 total 1312 skew    0 clock  60.02KHz
        v: height  768 start  769 end  772 total  800           clock  75.03Hz
  1024x768 (0x57) 75.000MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1328 skew    0 clock  56.48KHz
        v: height  768 start  771 end  777 total  806           clock  70.07Hz
  1024x768 (0x58) 65.000MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock  48.36KHz
        v: height  768 start  771 end  777 total  806           clock  60.00Hz
  832x624 (0x59) 57.284MHz -HSync -VSync
        h: width   832 start  864 end  928 total 1152 skew    0 clock  49.73KHz
        v: height  624 start  625 end  628 total  667           clock  74.55Hz
  800x600 (0x5a) 50.000MHz +HSync +VSync
        h: width   800 start  856 end  976 total 1040 skew    0 clock  48.08KHz
        v: height  600 start  637 end  643 total  666           clock  72.19Hz
  800x600 (0x5b) 49.500MHz +HSync +VSync
        h: width   800 start  816 end  896 total 1056 skew    0 clock  46.88KHz
        v: height  600 start  601 end  604 total  625           clock  75.00Hz
  800x600 (0x5c) 40.000MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock  37.88KHz
        v: height  600 start  601 end  605 total  628           clock  60.32Hz
  720x576 (0x5d) 27.000MHz -HSync -VSync
        h: width   720 start  732 end  796 total  864 skew    0 clock  31.25KHz
        v: height  576 start  581 end  586 total  625           clock  50.00Hz
  720x576i (0x5e) 13.500MHz -HSync -VSync Interlace
        h: width   720 start  732 end  795 total  864 skew    0 clock  15.62KHz
        v: height  576 start  580 end  586 total  625           clock  50.00Hz
  720x480 (0x5f) 27.027MHz -HSync -VSync
        h: width   720 start  736 end  798 total  858 skew    0 clock  31.50KHz
        v: height  480 start  489 end  495 total  525           clock  60.00Hz
  720x480 (0x60) 27.000MHz -HSync -VSync
        h: width   720 start  736 end  798 total  858 skew    0 clock  31.47KHz
        v: height  480 start  489 end  495 total  525           clock  59.94Hz
  720x480i (0x61) 13.514MHz -HSync -VSync Interlace
        h: width   720 start  739 end  801 total  858 skew    0 clock  15.75KHz
        v: height  480 start  488 end  494 total  525           clock  60.00Hz
  720x480i (0x62) 13.500MHz -HSync -VSync Interlace
        h: width   720 start  739 end  801 total  858 skew    0 clock  15.73KHz
        v: height  480 start  488 end  494 total  525           clock  59.94Hz
  640x480 (0x63) 31.500MHz -HSync -VSync
        h: width   640 start  656 end  720 total  840 skew    0 clock  37.50KHz
        v: height  480 start  481 end  484 total  500           clock  75.00Hz
  640x480 (0x64) 31.500MHz -HSync -VSync
        h: width   640 start  664 end  704 total  832 skew    0 clock  37.86KHz
        v: height  480 start  489 end  492 total  520           clock  72.81Hz
  640x480 (0x65) 30.240MHz -HSync -VSync
        h: width   640 start  704 end  768 total  864 skew    0 clock  35.00KHz
        v: height  480 start  483 end  486 total  525           clock  66.67Hz
  640x480 (0x66) 25.200MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock  31.50KHz
        v: height  480 start  490 end  492 total  525           clock  60.00Hz
  640x480 (0x67) 25.175MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock  31.47KHz
        v: height  480 start  490 end  492 total  525           clock  59.94Hz
  720x400 (0x68) 28.320MHz -HSync +VSync
        h: width   720 start  738 end  846 total  900 skew    0 clock  31.47KHz
        v: height  400 start  412 end  414 total  449           clock  70.08Hz

aBUGSworstnightmare
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Re: Pi 400 too?

Tue Aug 10, 2021 5:39 am

cspan wrote:
Mon Aug 09, 2021 1:36 pm
aBUGSworstnightmare wrote:
Mon Aug 09, 2021 3:11 am
find the failure: 64bit BETA!
I'm using the HDMI port closest to the USB-C power port.
sure? Below output tells a different story.

Code: Select all

pi@pi400:~ $ xrandr --verbose
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 7680 x 7680
HDMI-1 disconnected primary (normal left inverted right x axis y axis)
...
HDMI-2 connected 1280x720+0+0 (0x53) normal (normal left inverted right x axis y axis) 609mm x 347mm
...
[/quote]

cspan
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Location: USA

Re: Pi 4/400/CM4 with 1366x768 display not working?

Tue Aug 10, 2021 11:44 am

Yes, I'm sure (just checked), but that is a curious result anyway, because the Pi is connected to HDMI-1 on the TV/Monitor. [We have a Roku in HDMI-2].

On the Pi side, it's definitely connected at the port immediately adjacent to the USB-C power port. As you look at it from the normal typing position, it's immediately to the right of the USB-C port. If instead looking at the ports straight-on, it's immediately to the left.

[it appears the two HDMI ports on the Pi are unlabeled ... and I've had difficulty finding where in the documentation they might be described. I have noticed that the one closest to the power port is referred to in the forums as "primary" ... perhaps even as HDMI-0, but I can't find anything official on that].

If booted from microSD with the SSD attached, it'll immediately load as an attached drive with rootfs and boot partitions. Without the microSD card, the SSD does not boot the Pi - in fact, it doesn't even send a signal out via HDMI, at least not one that the monitor receives.

FWIW I imaged the OS directly to the SSD using Raspberry Pi Imager in Linux Mint.

6by9
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Re: Pi 4/400/CM4 with 1366x768 display not working?

Tue Aug 10, 2021 12:08 pm

cspan wrote:
Tue Aug 10, 2021 11:44 am
Yes, I'm sure (just checked), but that is a curious result anyway, because the Pi is connected to HDMI-1 on the TV/Monitor. [We have a Roku in HDMI-2].

On the Pi side, it's definitely connected at the port immediately adjacent to the USB-C power port. As you look at it from the normal typing position, it's immediately to the right of the USB-C port. If instead looking at the ports straight-on, it's immediately to the left.

[it appears the two HDMI ports on the Pi are unlabeled ... and I've had difficulty finding where in the documentation they might be described. I have noticed that the one closest to the power port is referred to in the forums as "primary" ... perhaps even as HDMI-0, but I can't find anything official on that].
Earlier posts imply you're on a Pi400 instead of Pi4.
Pi400 I believe the connector further from the USB-C is HDMI-1, with the one next to it is HDMI-2.
Software Engineer at Raspberry Pi Ltd. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

cspan
Posts: 375
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Location: USA

Re: Pi 4/400/CM4 with 1366x768 display not working?

Tue Aug 10, 2021 12:49 pm

6by9 wrote:
Tue Aug 10, 2021 12:08 pm
Earlier posts imply you're on a Pi400 instead of Pi4.
Pi400 I believe the connector further from the USB-C is HDMI-1, with the one next to it is HDMI-2.
That is true, I'm on a Pi 400. Good to know on the terminology. That said, since it boots fine using microSD and connected to the HDMI port nearest USB-C, ought I move it to the other HDMI port on the Pi to boot via USB/SSD? In other words, does the type of boot media affect which HDMI port should be used for single-monitor use?

6by9
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Re: Pi 4/400/CM4 with 1366x768 display not working?

Tue Aug 10, 2021 1:13 pm

cspan wrote:
Tue Aug 10, 2021 12:49 pm
That is true, I'm on a Pi 400. Good to know on the terminology. That said, since it boots fine using microSD and connected to the HDMI port nearest USB-C, ought I move it to the other HDMI port on the Pi to boot via USB/SSD? In other words, does the type of boot media affect which HDMI port should be used for single-monitor use?
Boot media shouldn't make any difference.
Only HDMI-1 supports 4k60, and then only with the relevant config.txt option, but otherwise it shouldn't make any difference.
Software Engineer at Raspberry Pi Ltd. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

cspan
Posts: 375
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Location: USA

Re: Pi 4/400/CM4 with 1366x768 display not working?

Tue Aug 10, 2021 5:30 pm

Good news, I got Pi to boot via USB/SSD, using the 32-bit PiOS (full). Doesn't seem to work on 64-bit beta however, not with my SSD anyway.

Not so good news: the option for 1366x768 display (or 1360 as indicated in documentation) still not shown in the Screen Configuration GUI, and specifying it in config.txt does not help. It's defaulting to 1920x1080, though my TV/Monitor does not have that high of a resolution, so small text looks pixelated a bit.

More later perhaps.

aBUGSworstnightmare
Posts: 6048
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pi 4/400/CM4 with 1366x768 display not working?

Fri Aug 13, 2021 5:33 am

cspan wrote:
Tue Aug 10, 2021 5:30 pm
Good news, I got Pi to boot via USB/SSD, using the 32-bit PiOS (full). Doesn't seem to work on 64-bit beta however, not with my SSD anyway.

Not so good news: the option for 1366x768 display (or 1360 as indicated in documentation) still not shown in the Screen Configuration GUI, and specifying it in config.txt does not help. It's defaulting to 1920x1080, though my TV/Monitor does not have that high of a resolution, so small text looks pixelated a bit.

More later perhaps.
you have
- added below lines to config.txt in the [all] section?

Code: Select all

 hdmi_group=2
hdmi_mode=87
hdmi_cvt=1360 768 60  
- made sure there is no other active line for hdmi_mode/group in your config.txt?

cspan
Posts: 375
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Re: Pi 4/400/CM4 with 1366x768 display not working?

Fri Aug 13, 2021 9:20 pm

I think so. Thanks - but just in case I missed something, here's my config.txt file for the Pi400:

Code: Select all

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
# For Samsung TV 1366x768
hdmi_group=2
hdmi_mode=87
hdmi_cvt=1360 768 60
Note, I did try enabling overscan, but it does not bring up the 1360x768 option.

aBUGSworstnightmare
Posts: 6048
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pi 4/400/CM4 with 1366x768 display not working?

Sat Aug 14, 2021 5:31 am

cspan wrote:
Fri Aug 13, 2021 9:20 pm
I think so. Thanks - but just in case I missed something, here's my config.txt file for the Pi400:

Code: Select all

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
# For Samsung TV 1366x768
hdmi_group=2
hdmi_mode=87
hdmi_cvt=1360 768 60
Note, I did try enabling overscan, but it does not bring up the 1360x768 option.
o.k. I have a 1366x768pixel display connected to my Pi400. Let me see what happens if I pretend to have another 1360x768 monitor on HDMI0 (HDMI-1 in case of xrandr naming). Will come back ..

aBUGSworstnightmare
Posts: 6048
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pi 4/400/CM4 with 1366x768 display not working?

Sat Aug 14, 2021 3:42 pm

tested - as promised this morning. My DUT is a Pi400 which has a 1366x768pixel module which I'm driving in 1364x768pixel resolution.

Adding below to my config.txt

Code: Select all

hdmi_force_hotplug:0=1
hdmi_ignore_edid:0=0xa5000080
hdmi_group:0=2
hdmi_mode:0=87
hdmi_cvt:0=1360 768 60
gives me this:
2021-08-14-173330_2724x768_scrot_scaled.jpg
Screenshot of the full desktop. My 12.3in is on the left side.
2021-08-14-173330_2724x768_scrot_scaled.jpg (38.35 KiB) Viewed 19455 times
screenconfigutil.jpg
Detail shot of the Screen Confiiguration utility. My panel is labeled as DSI-1 (it's connected by DPI), and the 1360x768pixel is HDMI-1
screenconfigutil.jpg (49.33 KiB) Viewed 19455 times

Code: Select all

pi@raspberrypi:~ $ xrandr --verbose
Screen 0: minimum 320 x 200, current 2724 x 768, maximum 7680 x 7680
DSI-1 connected primary 1364x768+0+0 (0x44) normal (normal left inverted right x axis y axis) 0mm x 0mm
	Identifier: 0x41
	Timestamp:  8950
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       0
	CRTCs:      0
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB: Automatic 
		supported: Automatic, Full, Limited 16:235
	bottom margin: 0 
		range: (0, 100)
	top margin: 0 
		range: (0, 100)
	right margin: 0 
		range: (0, 100)
	left margin: 0 
		range: (0, 100)
	link-status: Good 
		supported: Good, Bad
	CONNECTOR_ID: 89 
		supported: 89
	non-desktop: 0 
		range: (0, 1)
  FIXED_MODE (0x44) 75.400MHz +HSync +VSync *current +preferred
        h: width  1364 start 1404 end 1405 total 1406 skew    0 clock  53.63KHz
        v: height  768 start  780 end  780 total  781           clock  68.66Hz
HDMI-1 connected 1360x768+1364+0 (0x45) normal (normal left inverted right x axis y axis) 0mm x 0mm
	Identifier: 0x42
	Timestamp:  8950
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       1
	CRTCs:      1
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB: Automatic 
		supported: Automatic, Full, Limited 16:235
	bottom margin: 0 
		range: (0, 100)
	top margin: 0 
		range: (0, 100)
	right margin: 0 
		range: (0, 100)
	left margin: 0 
		range: (0, 100)
	link-status: Good 
		supported: Good, Bad
	CONNECTOR_ID: 153 
		supported: 153
	non-desktop: 0 
		range: (0, 1)
  FIXED_MODE (0x45) 84.750MHz +HSync +VSync *current +preferred
        h: width  1360 start 1432 end 1568 total 1776 skew    0 clock  47.72KHz
        v: height  768 start  771 end  773 total  798           clock  59.80Hz
pi@raspberrypi:~ $ 

cspan
Posts: 375
Joined: Sat Jun 10, 2017 1:03 pm
Location: USA

Re: Pi 4/400/CM4 with 1366x768 display not working?

Sun Aug 15, 2021 12:50 pm

aBUGSworstnightmare,

Thanks for your edits and screenshots. I'm not sure to what degree they apply to my situation, but I'll play around with the settings, in light of the myriad of options listed in documentation, and see what results. I suppose struggling through this can be seen as tuition in the RPi school of computer education.

What puzzles me is that the settings in the documentation under "Raspberry Pi 4 HDMI Pipeline" used to work for me just fine in getting the most out of my TV-as-monitor. They no longer do.

Related matter, I do wonder about that and other areas of the documentation that specify Raspberry Pi 4 ... how many of those also apply to Raspberry Pi 400? All? Some? Unless the answer is none (i.e., taking it literally as only applying to the 4), it's not clear.

I may try to set hdmi_mode=39, or 86 (reduced blanking). Either of those should provide superior resolution to 1280x720, but I don't know if I can force it to that. My TV display modes are:
Samsung_DMT_3.png
Samsung_DMT_3.png (135.51 KiB) Viewed 19405 times

aBUGSworstnightmare
Posts: 6048
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pi 4/400/CM4 with 1366x768 display not working?

Sun Aug 15, 2021 1:36 pm

cspan wrote:
Sun Aug 15, 2021 12:50 pm
aBUGSworstnightmare,

Thanks for your edits and screenshots. I'm not sure to what degree they apply to my situation, but I'll play around with the settings, in light of the myriad of options listed in documentation, and see what results. I suppose struggling through this can be seen as tuition in the RPi school of computer education.

What puzzles me is that the settings in the documentation under "Raspberry Pi 4 HDMI Pipeline" used to work for me just fine in getting the most out of my TV-as-monitor. They no longer do.

Related matter, I do wonder about that and other areas of the documentation that specify Raspberry Pi 4 ... how many of those also apply to Raspberry Pi 400? All? Some? Unless the answer is none (i.e., taking it literally as only applying to the 4), it's not clear.

I may try to set hdmi_mode=39, or 86 (reduced blanking). Either of those should provide superior resolution to 1280x720, but I don't know if I can force it to that. My TV display modes are:

Samsung_DMT_3.png
Pi4 and Pi400 were using same SOC, so any spec which is related to the SOC applies for both.

Did you even try the settings which I've posted? They will force a resolution of 1360x768pixels, so exactly what you want.

Sorry, but as I don't have a monitor which such resolution I can not test any further, but that's up to you to test what's been proposed and report back.
In case you don't understand what the commands will do I can only point you to the documentation; all explained there.

cspan
Posts: 375
Joined: Sat Jun 10, 2017 1:03 pm
Location: USA

Re: Pi 4/400/CM4 with 1366x768 display not working?

Sun Aug 15, 2021 2:54 pm

aBUGSworstnightmare wrote:
Sun Aug 15, 2021 1:36 pm
Did you even try the settings which I've posted? They will force a resolution of 1360x768pixels, so exactly what you want.
I will; I just haven't gotten to it yet - I will in the next few hours. I'll post my results. Again, thank you for those.

Edit to update:

By applying your recommended edits, it definitely did something, but not all was expected or effective.
The first thing I noticed was that the screen ran off the right hand side ... from the top menu bar, the affected icons were the time and the speaker/sound icon (half gone). Fiddling with overscan only caused the screen to shrink substantially.

The second thing was, the GUI application "Screen Configuration" now had me with two screens (HDMI-1, HDMI-2) even though I only have one screen connected via HDMI cable. HDMI-1 had defined resolution "FIXEDMODE" and HDMI-2 defaulted to 1280x720.
Raspi-config had more options, including options 86 and 87, but again, the screen ran off the right hand side.

I played around with commenting out the ignore_edid, then the force_hotplug (each alone, then together). Nothing gave me a 1360x766 option in Screen Configuration, or a working one in raspi-config.

Finally I did some troubleshooting from the Documentation section, "Which values are valid for my monitor" - running the DMT values only (since my TV manual doesn't mention CEA), I got 4, 5, 6, 9, 10, 11, 16, 17, 18, 85. Nothing related to 1366x768, which was sort of expected ... as the documentation notes for the Pi 4 and HDMI Pipeline, you have to try to trick it to get to hdmi_cvt=1360 768 60 (slotting it in under group 2, mode 87). Now, if I also need to fiddle with the hmdi_timings, well that's another mountain to climb, perhaps for another day.

Thanks again!

P.S. the Documentation's step 5 for "which values are valid for my monitor" - dumping more detailed info from my monitor to edid.dat - just wrote a half-dozen lines of garbage/garbled characters except for one word, "Samsung".

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