choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Raspberry Pi 4 Camera stop working when Touchscreen connected

Wed Nov 23, 2022 4:20 pm

Here is my setup: -
OS: Ubuntu 20.04.4 LTS
Camera: Arducam OV9281 (dtoverlay=ov9281 defined in /boot/firmware/config.txt)
Touchscreen: Raspberry Pi 7 Inch Touch Screen Display

I've tested the following cases: -
(1) Connect arducam camera only:
camera - ok
(2) Connect touchscreen only:
touchscreen - ok
(3) Connect both touchscreen & arducam camera:
touchscreen - ok but camera - NOT DETECTED
PS: I've tried also to supply separate power supply to touchscreen but getting the same result as above. I believe it's not due to power supply issue.

I've read similar topic viewtopic.php?t=317414 with a raspberry engineer quoted below:
6by9 quoted: libcamera uses kernel drivers for the camera control which will conflict with the touchscreen which defaults to being polled by the firmware.
Question: I'm using ov9281 overlay and may I know if this is conflicting with the touchscreen? I've tested with raspberry pi official camera without overlay and both official raspberry camera & touch screen works fine.

6by9 quoted: it is possible to configure the kernel drivers to read it directly.
Question: May I know how and if I configure kernel drivers for the Touchscreen, will it avoid conflicting with the camera and solve my problem?

Thanks!

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13533
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Thu Nov 24, 2022 11:43 am

We don't support Ubuntu, and I couldn't even say for certain what defaults they use over the display stack or kernel version.
On Raspberry Pi OS, config.txt would have

Code: Select all

dtoverlay=vc4-kms-v3d
display_auto_detect=1
which will use the edt-ft5x04 kernel driver for the touchscreen (and kernel drivers to driver the display itself too).

You may be able to do a hybrid vc4-fkms-v3d configuration by using

Code: Select all

dtoverlay=vc4-fkms-v3d
disable_touchscreen=1
dtoverlay=edt-ft5406
but I can't guarantee that it will work.

In either case you would retain the "dtoverlay=ov9281" to configure the camera module.
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.

choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Thu Nov 24, 2022 3:47 pm

Hi 6by9, I'm lucky to have the same engineer replying by post, thanks! This is my test for both cases:

Code: Select all

dtoverlay=vc4-kms-v3d
display_auto_detect=1
Result: touchscreen shows only boot status but turns to blank screen when it should show a login screen, camera works ok

Code: Select all

dtoverlay=vc4-fkms-v3d
disable_touchscreen=1
dtoverlay=edt-ft5406
Result: touchscreen shows login screen but no response to screen touches, camera still NOT working with below message:
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
VIDIOC_STREAMON returned -1 (Input/output error)
May I know if there are any options you can think of and let me try it out? In the worst case scenario, will it work if I switch the OS to Raspbian?

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13533
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Thu Nov 24, 2022 4:31 pm

choongteck wrote:
Thu Nov 24, 2022 3:47 pm

Code: Select all

dtoverlay=vc4-kms-v3d
display_auto_detect=1
Result: touchscreen shows only boot status but turns to blank screen when it should show a login screen, camera works ok
What kernel version are you running? "uname -a"
choongteck wrote:

Code: Select all

dtoverlay=vc4-fkms-v3d
disable_touchscreen=1
dtoverlay=edt-ft5406
Result: touchscreen shows login screen but no response to screen touches, camera still NOT working with below message:

Code: Select all

pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
                VIDIOC_STREAMON returned -1 (Input/output error)
Media controller almost certainly means that won't work as the two entities disagree on formats - viewtopic.php?t=322076
If you just want the raw images rather than using libcamera, use

Code: Select all

dtoverlay=ov9281,media-controller=0
choongteck wrote:May I know if there are any options you can think of and let me try it out? In the worst case scenario, will it work if I switch the OS to Raspbian?
Check which modules are loaded using "lsmod".

You've just reminded me that I do have an Ubuntu 22.04 SD card here. That is running vc4-kms-v3d and a 5.15 kernel, so is probably the better route if you want Ubuntu rather than Raspberry Pi OS.
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.

choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Thu Nov 24, 2022 5:24 pm

Here is my uname:

Code: Select all

pi@ubuntu:~$ uname -a
Linux ubuntu 5.4.0-1074-raspi #85-Ubuntu SMP PREEMPT Fri Nov 4 13:34:24 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
Thanks for the link, not quite sure if/how the media-controller will affect my project, but I'm just using the raw/compressed images captured from ov9281 camera and send to ROS for processing. I've tried adding media-controller=0 and re-tested both cases you suggested earlier and hoping my camera & touchscreen will magically work; unfortunately results are similar in both cases.

Here is my output from lsmod:

Code: Select all

pi@ubuntu:~$ lsmod
Module                  Size  Used by
bnep                   36864  2
binfmt_misc            24576  1
dm_multipath           36864  0
scsi_dh_rdac           16384  0
scsi_dh_emc            16384  0
scsi_dh_alua           24576  0
btsdio                 20480  0
bluetooth             634880  8 btsdio,bnep
ecdh_generic           16384  1 bluetooth
ecc                    36864  1 ecdh_generic
brcmfmac              397312  0
brcmutil               28672  1 brcmfmac
bcm2835_codec          45056  0
cfg80211              839680  1 brcmfmac
bcm2835_isp            28672  0
bcm2835_v4l2           49152  0
ov9281                 20480  1
bcm2835_unicam         45056  0
bcm2835_mmal_vchiq     45056  3 bcm2835_codec,bcm2835_v4l2,bcm2835_isp
v4l2_mem2mem           36864  1 bcm2835_codec
videobuf2_vmalloc      20480  1 bcm2835_v4l2
v4l2_fwnode            32768  2 ov9281,bcm2835_unicam
v4l2_dv_timings        36864  1 bcm2835_unicam
videobuf2_dma_contig    24576  3 bcm2835_codec,bcm2835_unicam,bcm2835_isp
videobuf2_memops       20480  2 videobuf2_vmalloc,videobuf2_dma_contig
videobuf2_v4l2         32768  5 bcm2835_codec,bcm2835_unicam,bcm2835_v4l2,v4l2_mem2mem,bcm2835_isp
videobuf2_common       61440  6 bcm2835_codec,videobuf2_v4l2,bcm2835_unicam,bcm2835_v4l2,v4l2_mem2mem,bcm2835_isp
raspberrypi_hwmon      16384  0
videodev              315392  9 bcm2835_codec,v4l2_fwnode,ov9281,videobuf2_v4l2,bcm2835_unicam,bcm2835_v4l2,videobuf2_common,v4l2_mem2mem,bcm2835_isp
vc_sm_cma              49152  2 bcm2835_mmal_vchiq,bcm2835_isp
mc                     73728  8 videodev,bcm2835_codec,ov9281,videobuf2_v4l2,bcm2835_unicam,videobuf2_common,v4l2_mem2mem,bcm2835_isp
snd_bcm2835            36864  2
rpivid_mem             16384  0
rpi_backlight          16384  0
uio_pdrv_genirq        16384  0
uio                    24576  1 uio_pdrv_genirq
sch_fq_codel           20480  2
ipmi_devintf           24576  0
ipmi_msghandler        61440  1 ipmi_devintf
ramoops                36864  0
reed_solomon           24576  1 ramoops
ip_tables              40960  0
x_tables               57344  1 ip_tables
autofs4                57344  2
btrfs                1433600  0
zstd_compress         163840  1 btrfs
raid10                 69632  0
raid456               184320  0
async_raid6_recov      24576  1 raid456
async_memcpy           20480  2 raid456,async_raid6_recov
async_pq               20480  2 raid456,async_raid6_recov
async_xor              20480  3 async_pq,raid456,async_raid6_recov
async_tx               20480  5 async_pq,async_memcpy,async_xor,raid456,async_raid6_recov
xor                    20480  2 async_xor,btrfs
xor_neon               16384  1 xor
raid6_pq              114688  4 async_pq,btrfs,raid456,async_raid6_recov
libcrc32c              16384  2 btrfs,raid456
raid1                  53248  0
raid0                  24576  0
multipath              24576  0
linear                 20480  0
i2c_mux_pinctrl        16384  0
i2c_mux                16384  1 i2c_mux_pinctrl
crct10dif_ce           16384  1
dwc2                  270336  0
vc4                   290816  9
udc_core               65536  1 dwc2
drm_kms_helper        229376  3 vc4
spidev                 24576  0
syscopyarea            16384  1 drm_kms_helper
sysfillrect            16384  1 drm_kms_helper
sysimgblt              16384  1 drm_kms_helper
v3d                    77824  3
fb_sys_fops            20480  1 drm_kms_helper
gpu_sched              45056  1 v3d
drm                   573440  11 gpu_sched,drm_kms_helper,v3d,vc4
snd_soc_core          262144  1 vc4
snd_compress           32768  1 snd_soc_core
phy_generic            20480  1
ac97_bus               16384  1 snd_soc_core
snd_pcm_dmaengine      16384  1 snd_soc_core
snd_pcm               143360  4 vc4,snd_bcm2835,snd_soc_core,snd_pcm_dmaengine
snd_timer              45056  1 snd_pcm
snd                   114688  9 snd_bcm2835,snd_timer,snd_compress,snd_soc_core,snd_pcm
aes_neon_bs            28672  1
aes_neon_blk           28672  1 aes_neon_bs
crypto_simd            20480  2 aes_neon_bs,aes_neon_blk
cryptd                 24576  1 crypto_simd
You've just reminded me that I do have an Ubuntu 22.04 SD card here. That is running vc4-kms-v3d and a 5.15 kernel, so is probably the better route if you want Ubuntu rather than Raspberry Pi OS.
Thanks for the suggestion! I will install Ubuntu 22.04 if there is no any other option for my current Ubuntu 20.04. May I ask if you're able to run both Touchscreen and *dtoverlay* camera (not raspberry official camera) in your Ubuntu 22.04 without problem I'm facing now?

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13533
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Thu Nov 24, 2022 7:19 pm

choongteck wrote:
Thu Nov 24, 2022 5:24 pm
Here is my uname:

Code: Select all

pi@ubuntu:~$ uname -a
Linux ubuntu 5.4.0-1074-raspi #85-Ubuntu SMP PREEMPT Fri Nov 4 13:34:24 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
Thanks for the link, not quite sure if/how the media-controller will affect my project, but I'm just using the raw/compressed images captured from ov9281 camera and send to ROS for processing. I've tried adding media-controller=0 and re-tested both cases you suggested earlier and hoping my camera & touchscreen will magically work; unfortunately results are similar in both cases.
5.4 - you've got almost no chance with vc4-kms-v3d then as it really needs at least 5.10 if not 5.15.

If you just want raw frames into ROS, then media-controller=0 is what you want as control is then solely through the /dev/videoN node. I couldn't say for certain whether the change enabling MC will have been in 5.4 (quite possibly not), in which case it may well have been a failure with the I2C that resulted in streaming failing.
choongteck wrote:
You've just reminded me that I do have an Ubuntu 22.04 SD card here. That is running vc4-kms-v3d and a 5.15 kernel, so is probably the better route if you want Ubuntu rather than Raspberry Pi OS.
Thanks for the suggestion! I will install Ubuntu 22.04 if there is no any other option for my current Ubuntu 20.04. May I ask if you're able to run both Touchscreen and *dtoverlay* camera (not raspberry official camera) in your Ubuntu 22.04 without problem I'm facing now?
I haven't tried. It's using vc4-kms-v3d, so I can be fairly confident that it will avoid the I2C conflict. Whether they have updated the kernel recently enough to solve all the issues I couldn't say for certain, but I'd expect so.
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.

choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Fri Nov 25, 2022 10:46 am

I've upgraded to Ubuntu 22.04, here is my uname:

Code: Select all

pi@ubuntu:~$ uname -a
Linux ubuntu 5.15.0-1018-raspi #20-Ubuntu SMP PREEMPT Fri Nov 4 18:20:53 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
It seems now Arducam camera will stop working whenever Touchscreen physical cables are connected to the Pi4 board with Ubuntu 22.04. In order for Arducam to work, media-controller=0 must be defined. Here are the results for the different cases:

(1) Arducam connected | Touchscreen NOT connected:

Code: Select all

(1.1)
dtoverlay=ov9281
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
                VIDIOC_STREAMON returned -1 (Invalid argument)

Code: Select all

(1.2)
dtoverlay=ov9281,media-controller=0
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 120.62 fps
(2) Both Arducam & Touchscreen connected:

Code: Select all

(2.1)
dtoverlay=ov9281,media-controller=0
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
Cannot open device /dev/video0, exiting.

Code: Select all

(2.2)
dtoverlay=ov9281,media-controller=0
dtoverlay=vc4-kms-v3d
display_auto_detect=1
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
                VIDIOC_STREAMON returned -1 (Input/output error)

Code: Select all

(2.3)
dtoverlay=ov9281,media-controller=0
dtoverlay=vc4-fkms-v3d
disable_touchscreen=1
dtoverlay=edt-ft5406
pi@ubuntu:~$ v4l2-ctl --stream-mmap --stream-count=-1 -d /dev/video0 --stream-to=/dev/null
                VIDIOC_STREAMON returned -1 (Input/output error)
I also noticed touchscreen repeating the following logs for case (2.3):

Code: Select all

i2c-bcm2835 fe205000.i2c: i2c transfer timed output
edt_ft5x06 10-0038: Unable to fetch data, error: -110
Here is my lsmod:

Code: Select all

pi@ubuntu:~$ lsmod
Module                  Size  Used by
cmac                   16384  3
algif_hash             24576  1
algif_skcipher         20480  1
af_alg                 32768  6 algif_hash,algif_skcipher
bnep                   32768  2
hci_uart              155648  1
btqca                  24576  1 hci_uart
btrtl                  24576  1 hci_uart
btbcm                  28672  1 hci_uart
btintel                45056  1 hci_uart
binfmt_misc            24576  1
btsdio                 20480  0
bluetooth             720896  30 btrtl,btqca,btsdio,btintel,hci_uart,btbcm,bnep
input_leds             16384  0
joydev                 32768  0
ecdh_generic           16384  2 bluetooth
ecc                    36864  1 ecdh_generic
brcmfmac              421888  0
brcmutil               28672  1 brcmfmac
bcm2835_unicam         61440  0
cfg80211              970752  1 brcmfmac
bcm2835_codec          53248  0
bcm2835_v4l2           49152  0
bcm2835_isp            36864  0
ov9281                 24576  1
v4l2_dv_timings        40960  1 bcm2835_unicam
v4l2_fwnode            32768  2 ov9281,bcm2835_unicam
v4l2_mem2mem           45056  1 bcm2835_codec
bcm2835_mmal_vchiq     40960  3 bcm2835_codec,bcm2835_v4l2,bcm2835_isp
raspberrypi_hwmon      16384  0
v4l2_async             28672  3 v4l2_fwnode,ov9281,bcm2835_unicam
videobuf2_vmalloc      20480  1 bcm2835_v4l2
videobuf2_dma_contig    24576  3 bcm2835_codec,bcm2835_unicam,bcm2835_isp
edt_ft5x06             32768  0
videobuf2_memops       20480  2 videobuf2_vmalloc,videobuf2_dma_contig
videobuf2_v4l2         32768  5 bcm2835_codec,bcm2835_unicam,bcm2835_v4l2,v4l2_mem2mem,bcm2835_isp
videobuf2_common       81920  9 bcm2835_codec,videobuf2_vmalloc,videobuf2_dma_contig,videobuf2_v4l2,bcm2835_unicam,bcm2835_v4l2,v4l2_mem2mem,videobuf2_memops,bcm2835_isp
videodev              282624  9 v4l2_async,bcm2835_codec,ov9281,videobuf2_v4l2,bcm2835_unicam,bcm2835_v4l2,videobuf2_common,v4l2_mem2mem,bcm2835_isp
snd_bcm2835            36864  0
mc                     73728  9 v4l2_async,videodev,bcm2835_codec,ov9281,videobuf2_v4l2,bcm2835_unicam,videobuf2_common,v4l2_mem2mem,bcm2835_isp
vc_sm_cma              45056  2 bcm2835_mmal_vchiq,bcm2835_isp
bcm2835_gpiomem        16384  0
rpivid_mem             16384  0
rpi_backlight          16384  0
nvmem_rmem             16384  0
uio_pdrv_genirq        20480  0
uio                    24576  1 uio_pdrv_genirq
sch_fq_codel           24576  2
dm_multipath           40960  0
pstore_blk             16384  0
pstore_zone            28672  1 pstore_blk
ramoops                32768  0
reed_solomon           28672  1 ramoops
ip_tables              36864  0
x_tables               61440  1 ip_tables
autofs4                49152  2
btrfs                1622016  0
blake2b_generic        24576  0
zstd_compress         229376  1 btrfs
raid10                 73728  0
raid456               196608  0
async_raid6_recov      24576  1 raid456
async_memcpy           20480  2 raid456,async_raid6_recov
async_pq               20480  2 raid456,async_raid6_recov
async_xor              20480  3 async_pq,raid456,async_raid6_recov
async_tx               20480  5 async_pq,async_memcpy,async_xor,raid456,async_raid6_recov
xor                    20480  2 async_xor,btrfs
xor_neon               16384  1 xor
hid_generic            16384  0
usbhid                 73728  0
raid6_pq              114688  4 async_pq,btrfs,raid456,async_raid6_recov
libcrc32c              16384  2 btrfs,raid456
raid1                  57344  0
raid0                  24576  0
multipath              24576  0
linear                 20480  0
spidev                 24576  0
vc4                   344064  0
snd_soc_core          311296  1 vc4
snd_compress           28672  1 snd_soc_core
snd_pcm_dmaengine      20480  1 snd_soc_core
snd_pcm               163840  4 snd_bcm2835,snd_compress,snd_soc_core,snd_pcm_dmaengine
v3d                    94208  0
gpu_sched              49152  1 v3d
i2c_mux_pinctrl        16384  0
dwc2                  315392  0
snd_timer              45056  1 snd_pcm
snd                   126976  5 snd_bcm2835,snd_timer,snd_compress,snd_soc_core,snd_pcm
crct10dif_ce           20480  1
i2c_mux                16384  1 i2c_mux_pinctrl
roles                  20480  1 dwc2
udc_core               73728  1 dwc2
drm_kms_helper        344064  3 vc4
syscopyarea            16384  1 drm_kms_helper
i2c_bcm2835            20480  0
spi_bcm2835            28672  0
sysfillrect            20480  1 drm_kms_helper
sysimgblt              16384  1 drm_kms_helper
fb_sys_fops            20480  1 drm_kms_helper
cec                    81920  2 drm_kms_helper,vc4
drm                   651264  5 gpu_sched,drm_kms_helper,v3d,vc4
xhci_pci               24576  0
xhci_pci_renesas       24576  1 xhci_pci
ac97_bus               16384  1 snd_soc_core
phy_generic            20480  1
aes_arm64              16384  3

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13533
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Fri Nov 25, 2022 11:32 am

The touchscreen microcontroller is very temperamental and can lock the I2C bus when upset. i2cdetect -y 10 will report all addresses as active in this situation, and annoyingly requires a power cycle of the screen.

I wish Ubuntu would retain the full kernel revision they build from, as 5.15.0 tells me nothing about the potential patch level.

You don't say whether the lsmod was from the vc4-fkms-3d or vc4-kms-v3d option. It includes rpi_backlight, so I presume fkms, and that backlight control may also be causing a conflict on the I2C. There's no easy way around that one.

Sorry, going to have to push this one back to Canonical for Ubuntu. I've just tried a fairly vanilla Raspberry Pi OS Bullseye image (5.15.32 kernel), and it works just fine with touch and camera when adding "dtoverlay=ov9281,media-controller=0".
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.

choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Sat Nov 26, 2022 6:53 pm

Hi 6by9, thanks for letting me know Raspberry Pi OS Bullseye works for both Arducam + Touchscreen; I've also tested with Bulleye and it works. I've been trying to install ROS packages that I need to use to Bulleye for past 2 days but got stuck with some compatibility issues from ROS, unfortunately ROS only supports Debian Buster at this moment.

I'm afraid I may need to try harder in Buster, may I ask what are the configurations should I define in config.txt so that Arducam + Touchscreen can works fine in Buster? I've tested the setup in Buster, unfortunately results looks similar to Ubuntu.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13533
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Sat Nov 26, 2022 8:42 pm

Use rpi-update to grab the latest kernel (if you want then look at the version that has been tagged as stable). All settings that you've used on Bullseye should then work on buster.
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.

choongteck
Posts: 6
Joined: Wed Nov 23, 2022 3:41 pm

Re: Raspberry Pi 4 Camera stop working when Touchscreen connected

Sun Nov 27, 2022 7:27 pm

Hi 6by9, I've upgraded kernel using rpi-update from Buster and both Arducam + Touchscreen works ok. However, need to seek your expert knowledge to understand more on the conflict as I am looking for workaround (or use another Touchscreen) to avoid conflict in Ubuntu:

Based on previous test cases, both dtoverlay=vc4-kms-v3d & dtoverlay=vc4-fkms-v3d will cause the conflict to Arducam. May I know if possible to NOT use the dtoverlay for Touchscreen and instead project the screen via HDMI and accept the touches through USB port? I've found other Touchscreen (https://www.waveshare.com/wiki/7inch_HDMI_LCD_(C)) that supports Raspberry Pi and use hdmi+usb but still need to use fkms dtoverlay, will this likely to have conflict also?

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