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:

Code: Select all
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"):

Code: Select all
[   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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Joined: Sun Nov 12, 2017 11:13 pm

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
 
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