[regression] RPI4B drm vc4: no crtc or sizes since 5.17 (works in 5.16; and still broken in at least 6.1)

Wed Mar 8 12:35:40 UTC 2023

Hi,

On Tue, Mar 07, 2023 at 05:10:16PM +0000, Dave Stevenson wrote:
> On Tue, 7 Mar 2023 at 16:25, AL13N <alien at rmail.be> wrote:
> > AL13N schreef op 2023-03-06 17:34:
> > > I have a RPI4B connected on 2nd HDMI port (furthest away from power)
> > > to a 4K TV, which works until 5.16, from 5.17 there is no X (or
> > > plymouth), the cause of no X is that EDID gives nothing, and in the
> > > journal; there is "Cannot find any crct or sizes". Only the kernel is
> > > changed for this.
> > >
> > > In 5.16 instead of this message there is a bunch of hex lines prefixed
> > > with BAD.
> > >
> > > It is still broken in 6.1 at the very least.
> > >
> > > I donno if this is related to this part, but I wanted to try a newer
> > > kernel, because the RPI4 seems to do all the video decoding in
> > > software and cannot seem to handle it.
> > >
> > >
> > > logs:
> > > vc4-drm gpu: bound fef05700.hdmi (ops vc4_hdmi_ops [vc4])
> > > vc4-drm gpu: bound fe004000.txp (ops vc4_txp_ops [vc4])
> > > vc4-drm gpu: bound fe206000.pixelvalve (ops vc4_crtc_ops [vc4])
> > > vc4-drm gpu: bound fe207000.pixelvalve (ops vc4_crtc_ops [vc4])
> > > vc4-drm gpu: bound fe20a000.pixelvalve (ops vc4_crtc_ops [vc4])
> > > vc4-drm gpu: bound fe216000.pixelvalve (ops vc4_crtc_ops [vc4])
> > > vc4-drm gpu: bound fec12000.pixelvalve (ops vc4_crtc_ops [vc4])
> > > checking generic (3ea81000 12c000) vs hw (0 ffffffffffffffff)
> > > fb0: switching to vc4 from simple
> > > Console: switching to colour dummy device 80x25
> > > [drm] Initialized vc4 0.0.0 20140616 for gpu on minor 0
> > > vc4-drm gpu: [drm] Cannot find any crtc or sizes
> >
> > 5.16 log has:
> >
> > vc4-drm gpu: bound fef05700.hdmi (ops vc4_hdmi_ops [vc4])
> > vc4-drm gpu: bound fe004000.txp (ops vc4_txp_ops [vc4])
> > vc4-drm gpu: bound fe206000.pixelvalve (ops vc4_crtc_ops [vc4])
> > vc4-drm gpu: bound fe207000.pixelvalve (ops vc4_crtc_ops [vc4])
> > vc4-drm gpu: bound fe20a000.pixelvalve (ops vc4_crtc_ops [vc4])
> > vc4-drm gpu: bound fe216000.pixelvalve (ops vc4_crtc_ops [vc4])
> > vc4-drm gpu: bound fec12000.pixelvalve (ops vc4_crtc_ops [vc4])
> > [drm] Initialized vc4 0.0.0 20140616 for gpu on minor 0
> >         [00] BAD  00 ff ff ff ff ff ff 00 36 74 00 00 00 00 00 00
> >         [00] BAD  0b 1f 01 03 00 23 01 78 0a cf 74 a3 57 4c b0 23
> >         [00] BAD  09 48 4c 00 00 00 01 01 01 ff 01 ff ff 01 01 01
> >         [00] BAD  01 01 01 01 01 20 08 e8 00 30 f2 70 5a 80 b0 58
> >         [00] BAD  8a 00 c4 8e 21 00 00 1e 02 3a 80 18 71 38 2d 40
> >         [00] BAD  58 2c 45 00 c4 8e 21 00 00 1e 00 00 00 fc 00 53
> >         [00] BAD  41 4c 4f 52 41 0a 20 20 20 20 20 20 00 00 00 fd
> >         [00] BAD  00 3b 46 1f 8c 3c 00 0a 20 20 20 20 20 20 01 aa
> > Console: switching to colour frame buffer device 240x67
> > vc4-drm gpu: [drm] fb0: vc4drmfb frame buffer device
> >
> >
> > i donno what this bad is, but it doesn't happen in 5.17... maybe these
> > BAD got filtered out, but they did end up working for me? or something?
> > i donno...
> 
> Run it through edid-decode - the checksum is wrong.
> 
> Block 0, Base EDID:
>   EDID Structure Version & Revision: 1.3
>   Vendor & Product Identification:
>     Manufacturer: MST
>     Model: 0
>     Made in: week 11 of 2021
>   Basic Display Parameters & Features:
>     Analog display
>     Input voltage level: 0.7/0.3 V
>     Blank level equals black level
>     Maximum image size: 35 cm x 1 cm
>     Gamma: 2.20
>     RGB color display
>     First detailed timing is the preferred timing
>   Color Characteristics:
>     Red  : 0.6396, 0.3398
>     Green: 0.2998, 0.6904
>     Blue : 0.1376, 0.0380
>     White: 0.2822, 0.2968
>   Established Timings I & II: none
>   Standard Timings:
>     GTF     :  2288x1432   61.000 Hz  16:10   90.463 kHz 282.245 MHz
>   Detailed Timing Descriptors:
>     DTD 1:  3840x2160   60.000 Hz  16:9   135.000 kHz 594.000 MHz (708
> mm x 398 mm)
>                  Hfront  176 Hsync  88 Hback 296 Hpol P
>                  Vfront    8 Vsync  10 Vback  72 Vpol P
>     DTD 2:  1920x1080   60.000 Hz  16:9    67.500 kHz 148.500 MHz (708
> mm x 398 mm)
>                  Hfront   88 Hsync  44 Hback 148 Hpol P
>                  Vfront    4 Vsync   5 Vback  36 Vpol P
>     Display Product Name: 'SALORA'
>   Display Range Limits:
>     Monitor ranges (GTF): 59-70 Hz V, 31-140 kHz H, max dotclock 600 MHz
>   Extension blocks: 1
> Checksum: 0xaa (should be 0xeb)
> 
> Weird that it also says that it's an analog display when it's
> connected over HDMI. Something rather bizarre there, and I think it'll
> hit problems in drm_edid at [1] as we end up with a connector having
> no color_formats defined. I was discussing this with Maxime only last
> week, but in relation to VGA monitors connected through HDMI to VGA
> adapters without rewriting the EDID.
>
> If you have an issue between 5.16 and 5.17, then I'd guess at [2] and
> your monitor not asserting hotplug correctly. The raw hotplug status
> is reported in /sys/kernel/debug/dri/N/hdmi0_regs (N will be either 0
> or 1 depending on the probe order of the vc4 and v3d drivers). Grep
> for HDMI_HOTPLUG.

If it's an option, bisecting between 5.16 and 5.17 which commit
introduced the regression would be nice.

> Incorrect hotplug behaviour causes grief when combined with HDMI2.0
> and scrambling. If you don' t know the other end has been
> disconnected, then you never know that scrambling needs to be
> re-negotiated over SCDC, and the display will typically end up just
> being blank.
> 
> [1] https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/drm_edid.c#L6460
> [2] https://github.com/torvalds/linux/commit/cc5f1cbbc1e12ad5b11d594159fe793eb03c70fa

We can easily test that: could you try booting with video=HDMI-A-1:D (or
HDMI-A-2, depending on whether you use HDMI0 or HDMI1) and see if it
helps?

> > I also noticed that earlier in the logs there are more bound lines:
> > (some are double)
> >
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> >
> > and then here for some reason systemd does modprobe at drm.service ? is
> > this just a delayed starting log line, or does it actually try to unload
> > drm and reload? i doubt it?
> > in any case there is more that appears before:
> >
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> > vc4-drm gpu: bound fef00700.hdmi (ops vc4_hdmi_ops [vc4])
> > vc4-drm gpu: bound fe400000.hvs (ops vc4_hvs_ops [vc4])
> > vc4-drm gpu: bound fef00700.hdmi (ops vc4_hdmi_ops [vc4])
> >
> >
> > so, the error message is weird, as it implies 2 possibilities. however,
> > i think it did find a crtc since all those pixelvalve things use crtc
> > functions?
> >
> > So then why do i have this problem on my RPI4? do most people just use
> > the raspberry pi kernels?
> 
> Largely, yes, people use our vendor kernels.

tbf, the downstream kernel has pretty much the same code here, so the
issue is very likely to affect it too.

I would just assume that your TV has some unusual behaviour that throws
the driver off, and most people won't.

Maxime