[Letux-kernel] GTA04 display and 5.10-rc5

[Andreas Kemnade]

On Mon, 30 Nov 2020 11:35:23 +0100
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> Hi Andreas,
> 
> > Am 30.11.2020 um 09:23 schrieb Andreas Kemnade <andreas at kemnade.info>:
> > 
> > Hi,
> > 
> > I am wondering whether I am the only one. I get a white screen only.
> > X11 detects the display but nothing is displayed. Seems to be a problem
> > on mainline. letux3704 display works with the same userspace.  
> 
> Well, I think I had tested it briefly and it was working, but I am not sure.
> 
> But - I now tried -rc6, -rc5, -rc4 and none is fully booting on the GTA04A5.
> 
> In most cases the GTA04A5 hangs after (once with a stack protector kernel panic):
> 
> [    3.104858] mmc0: new high speed SDHC card at address 59b4
> [    3.112091] oprofile: using arm/armv7
> [    3.117980] mmcblk0: mmc0:59b4 USDU1 29.8 GiB 
> [    3.123107] ThumbEE CPU extension supported.
> [    3.129333] Registering SWP/SWPB emulation handler
> 
> Strangely I also can no longer boot 5.9.10 nor 5.9.1. Only 5.4.79 did boot.
> 5.9.1 did boot well on the GTA04A4 after swapping the µSD into it... So it does
> not depend on µSD content but hardware...
> 
So is the 1Ghz stuff involved. I have also seen these bugs, the
typically seem to disappear if I either remove pvrsgx modules or attach
a serial cable :-( 

> 5.10-rc6 boots on the A4 but I also have a white display...
> 5.10-rc5 also has a white display on the A4...
> 5.10-rc4 panel works
> 
> So this makes it clear that it is the new omapdrm-mipi-dsi series which I
> have started to integrate into letux-5.10-rc5.
> 
omap2plus_defconfig + SPI bitbang enabled on 5.10-rc5 also does not
work.

> This series seems to break drivers/gpu/drm/panel/panel-tpo-td028ttec1.c
> while the Letux3704 uses one of the drivers/gpu/drm/panel/panel-simple.c
> definitions. This explains why there is another difference between your
> devices.
> 
Yes, and probably some internals are working differently.

> So something in Tomis series seems to break DPI with the specific driver.
> The same may happen for VENC so we have to look at it as well.
> 
Probably not,  since I tested it without.

> And some other bug makes the GTA04A5 boot less reliable between 5.4 and 5.9.
> 
> The big question is what...
> 
> Have you tried upstream 5.10-rc5 with omap2plus_defconfig?
> 
yes, see above. maybe I should also try 5.10-rc3.

Regards,
Andreas