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

[Nathan Ciobanu]

On Mon, Jan 06, 2020 at 08:08:04AM +0000, Lucien_Kao at compal.com wrote:
> 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.

Takashi, can you point to the patch series you suspect may have fixed this issue? 

Thanks,
Nathan
> 
> 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.ciobanu at linux.intel.com; Wang. CindyXT (TPE) <CindyXT_Wang at compal.com>; Ye. Nelson (TPE) <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 least 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 really mandatory.  I'm wondering whether the recent write-sync change improves the situation, 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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