questions/issue with dtoverlay=vc4-kms-v3d

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questions/issue with dtoverlay=vc4-kms-v3d

Postby 2sdude » Tue Jan 18, 2022 2:50 pm

I have an RPI3B.
I believe that only after the kernel naming change (to rpi(-legacy)) my boot/config.txt included:

$this->bbcode_second_pass_code('', 'dtoverlay=vc4-kms-v3d')

At any rate, (whether the line was present prior to the naming change or not) my RPI 7inch screen printed the boot messages and subsequently faded, started shaking, became unreadable.

I further spotted the following in the logs (NOTE "Cannot find any crtc or sizes"):

$this->bbcode_second_pass_code('', '
[ 11.978870] fb0: switching to vc4drmfb from simple
[ 12.048494] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 12.312775] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 12.319515] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[ 12.319779] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
[ 12.319938] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 12.320058] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 12.320176] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 12.320266] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
[ 12.327259] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
[ 12.327723] vc4-drm soc:gpu: [drm] Cannot find any crtc or sizes
[ 22.888678] vc4-drm soc:gpu: [drm] Cannot find any crtc or sizes
')

I found two fixes:
- use fake kms, change the line to: dtoverlay=vc4-fkms-v3d
- remove the line, seems my RPI3B use case doesn't require use of kms

Questions:
- would I need kms for running X server only? (anybody have a link that would help me understand the various cmdline.txt and boot.txt parameters?)
- do I need to set a screen size in /boot/cmdline.txt? Or using another parameter?
2sdude
 
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Re: questions/issue with dtoverlay=vc4-kms-v3d

Postby graysky » Tue Jan 18, 2022 3:11 pm

You might want to ask this on the official rpi forum if you cannot find the answer here: https://forums.raspberrypi.com/viewforum.php?f=29
graysky
Developer
 
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