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Message-ID: <c9e3a8f1-d053-4203-a364-0d0703fafd19@molgen.mpg.de>
Date:   Tue, 21 Nov 2023 16:08:54 +0100
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From:   Paul Menzel <pmenzel@molgen.mpg.de>
To:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>
Cc:     dri-devel@lists.freedesktop.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Powered off Philips TV sends corrupt EDID causing flickering
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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@lists.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?


Kind regards,

Paul