[alsa-devel] USB Type-C monitor flashes once when play a video file after unplug and re-plug the monitor

[Lucien_Kao at compal.com]

Hi Takashi

We verified on Ubuntu 19.10 with kernel 5.4.0.0-050400-generic (please refer to
attachment), the result is positive which symptom doesn't happen anymore once I
played music or video sound output through Dell S2718D Type-C monitor. It seems
had some fix in latest kernel.

Thanks.


-----Original Message-----
From: Takashi Iwai <tiwai at suse.de>
Sent: Friday, January 3, 2020 5:16 PM
To: Cheng. AJ (TPE) <AJ_Cheng at compal.com>
Cc: intel-gfx at lists.freedesktop.org; alsa-devel at alsa-project.org; nathan.d.cioba
nu at linux.intel.com; Wang. CindyXT (TPE) <CindyXT_Wang at compal.com>; Ye. Nelson (T
PE) <Nelson_Ye at compal.com>; Yap. Shane (TPE) <Shane_Yap at compal.com>; Kao. Lucien
 (TPE) <Lucien_Kao at compal.com>; Tseng. Evan (TPE) <Evan_Tseng at compal.com>
Subject: Re: [alsa-devel] USB Type-C monitor flashes once when play a video file
 after unplug and re-plug the monitor

On Fri, 03 Jan 2020 02:57:03 +0100,
<AJ_Cheng at compal.com> wrote:
>
> Hi Sirs,
>         Here is chromebook SW team from Compal.
> As the mail title, we hit issue that the external monitor will flash once when
 play video after hot pluging.
> We can reproduce not only on chromebook but also ubuntu 16.04.
> There has higher failure rate with Dell Solomon dock and Dell S2718D monitor.
>
> We found adding the delay in "sound/pci/hda/patch_hdmi.c " can fix
> this issue.(as the attachment) May need your help to review and advice. Thanks
.
>
> Here is the issue number in gitlab for more detail.
> https://gitlab.freedesktop.org/drm/intel/issues/318

Could you check whether it still happens with the latest upstream kernel, at lea
st 5.4.y, if it wasn't tested yet?

I don't want to put a long delay just because of random reason unless it's reall
y mandatory.  I'm wondering whether the recent write-sync change improves the si
tuation, so let's check the recent code.


thanks,

Takashi

>
>
>
> AJ Cheng
> NID/NID1
> e-mail: AJ_Cheng at compal.com<mailto:AJ_Cheng at compal.com>
> Tel:  +886-2-8797-8599 ext. 17561
> Mobile : +886-932827829
> COMPAL Electronics, Inc.
>
> [2 flash_once.diff <application/octet-stream (base64)>]
>
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> Alsa-devel at alsa-project.org
> https://mailman.alsa-project.org/mailman/listinfo/alsa-devel


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