linux-kernel - Re: Powered off Philips TV sends corrupt EDID causing flickering

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Message-ID: <87leaqm5sl.fsf@intel.com>
Date:   Wed, 22 Nov 2023 12:38:34 +0200
From:   Jani Nikula <jani.nikula@...ux.intel.com>
To:     Paul Menzel <pmenzel@...gen.mpg.de>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        dri-devel@...ts.freedesktop.org
Subject: Re: Powered off Philips TV sends corrupt EDID causing flickering

On Tue, 21 Nov 2023, Paul Menzel <pmenzel@...gen.mpg.de> wrote:
> Dear Linux folks,
>
>
> Connecting a USB Type-C port replicator [1] to the only USB Type-C port 
> of the Dell XPS 13 9360 with Debian sid/unstable and Debian’s Linux 
> kernel 6.10.5, and then connecting a Philips 40PFL5206H/12 TV device, 
> that is powered off or in standby, to the HDMI port, Linux logs:
>
> ```
> [    0.000000] Linux version 6.5.0-4-amd64 
> (debian-kernel@...ts.debian.org) (gcc-13 (Debian 13.2.0-6) 13.2.0, GNU 
> ld (GNU Binutils for Debian) 2.41) #1 SMP PREEMPT_DYNAMIC Debian 
> 6.5.10-1 (2023-11-03)
> […]
> [    0.000000] DMI: Dell Inc. XPS 13 9360/0596KF, BIOS 2.21.0 06/02/2022
> […]
> [  160.004836] EDID has corrupt header
> [  160.004866] 	[00] BAD  00 00 00 00 00 00 00 00 00 7f ff ff ff ff ff ff
> [  160.004875] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004881] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004886] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004905] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004911] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004917] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.004921] 	[00] BAD  ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [  160.013662] Registered IR keymap rc-cec
> [  160.014001] rc rc0: DP-1 as /devices/pci0000:00/0000:00:02.0/rc/rc0
> [  160.014305] input: DP-1 as 
> /devices/pci0000:00/0000:00:02.0/rc/rc0/input33
> [  160.228342] EDID has corrupt header
> [  160.408917] EDID has corrupt header
> ```
>
> The internal display of the laptop also switches off shortly, but comes 
> back after two or three seconds. This is very likely due to me 
> configuring the internal display to turn off once an external display is 
> used.
>
> No idea, why the TV is able to transmit anything at all, when it is 
> turned/powered off. To avoid the flickering, would it be possible to 
> ignore events from displays sending such incorrect EDID?

Depending on how the port replicator works, this may not come from the
TV at all.

And all of this probably depends on GPU and driver, which are not
mentioned.

If it's i915, please see [1] on how to file a bug.

Thanks,
Jani.


[1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html

>
>
> Kind regards,
>
> Paul

-- 
Jani Nikula, Intel