Re: [PATCH v1] drm/modes: Skip invalid cmdline mode

From: Maxime Ripard
Date: Wed Jul 10 2019 - 09:06:22 EST

On Wed, Jul 10, 2019 at 03:59:55PM +0300, Dmitry Osipenko wrote:
> 10.07.2019 15:55, Maxime Ripard ÐÐÑÐÑ:
> > On Wed, Jul 10, 2019 at 03:42:28PM +0300, Dmitry Osipenko wrote:
> >> 10.07.2019 13:12, Maxime Ripard ÐÐÑÐÑ:
> >>> On Tue, Jul 09, 2019 at 05:51:51PM +0300, Dmitry Osipenko wrote:
> >>>> The named mode could be invalid and then cmdline parser misses to validate
> >>>> mode's dimensions, happily adding 0x0 mode as a valid mode. One case where
> >>>> this happens is NVIDIA Tegra devices that are using downstream bootloader
> >>>> which adds "video=tegrafb" to the kernel's cmdline and thus upstream Tegra
> >>>> DRM driver fails to probe because of the invalid mode.
> >>>>
> >>>> Fixes: 3aeeb13d8996 ("drm/modes: Support modes names on the command line")
> >>>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> >>>
> >>> Applied to drm-misc-next-fixes
> >>>
> >>> Thanks for figuring this out!
> >>
> >> Thank you very much! So the driver now doesn't fail to probe because
> >> of the cmdline, but what else I noticed is that the framebuffer
> >> console is now rotated by 90Â on a 800x1280 panel, while display in
> >> Xorg is vertical as it was before. Seems something else is still
> >> missing, reverting "drm/modes: Rewrite the command line parser"
> >> returns the framebuffer's console orientation into the original
> >> state.
> >
> > What is the whole command line passed by the bootloader ?
> tegraid= mem=1022M@2048M android.commchip=0 vmalloc=512M androidboot.serialno=015d3f18c9081210 video=tegrafb no_console_suspend=1 console=none
> debug_uartport=hsport usbcore.old_scheme_first=1 lp0_vec=8192@0xbddf9000 tegra_fbmem=8195200@0xabe01000 core_edp_mv=0 audio_codec=rt5640 board_info=f41:a00:1:44:2
> root=/dev/sda1 rw rootwait tegraboot=sdmmc gpt gpt_sector=61079551 androidboot.bootloader=4.23 androidboot.baseband=1231_0.18.0_0409


It still doesn't really make sense to me why that video=tegrafb should
be considered valid.

However, I don't see anything rotation related in the commit you
list. Are you sure it's really the offending one and not another one?

Also, do you have the option to recompile a kernel so that we can add
some debug?


Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering

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