From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.yourmailgateway.de (relay.yourmailgateway.de [188.68.63.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 512F722A80D for ; Tue, 7 Jul 2026 08:51:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=188.68.63.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783414320; cv=none; b=Nxg2IuAxN1VQez/5G4r+DpdzOpTDd9xE+rM3kzCv34lqGDhSQUV749tkg/avBTvT2g/qHO2biMZ/IA4KO6IUNAOUTe0tviLBImzV4yrI8op6/NdWLcM9GwFWJsQBtat9CQQFGBjV0oOpuW9khg76xMtScKwGzwe2Z/B/vyB6gEE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783414320; c=relaxed/simple; bh=qAvw60k//6hFjyNyqu7YYOWF+8zLu93HZ24O0efrTCw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sM9bh75noZCTTxWLn55b5bBojsH0blfh11l3QUn1CgPup/KpP1GvHl/SJ6XA5sGar6wTaNRxaZ3TViNqt+z9XmFwEWlpqqaTGquxsMZFBE3Z8DxPFD0lV5flOHpJrpJ52bbjOCMAdqQRyym2kq+fDPafcvzY6gWYL9SoNK91h+g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=leemhuis.info; spf=pass smtp.mailfrom=leemhuis.info; dkim=pass (2048-bit key) header.d=leemhuis.info header.i=@leemhuis.info header.b=YrgSOQBF; arc=none smtp.client-ip=188.68.63.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=leemhuis.info Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=leemhuis.info Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=leemhuis.info header.i=@leemhuis.info header.b="YrgSOQBF" Received: from mors-relay8204.netcup.net (localhost [127.0.0.1]) by mors-relay8204.netcup.net (Postfix) with ESMTPS id 4gvZj31W9Kz8n1M; Tue, 7 Jul 2026 08:51:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=leemhuis.info; s=key2; t=1783414311; bh=qAvw60k//6hFjyNyqu7YYOWF+8zLu93HZ24O0efrTCw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=YrgSOQBFmrjB93rhJpD2TtOEeloLXK1usWWnBgVS+BaWUwyLwPYLzd9F8Ab+8teti BBp5Vh9q9le4Sl7QlCAOAyDElu85XFUnda01s/AFn9AtJd7Lz0rDVVG7b26HvhdHKY ANPETsitGFWHsxpde9Q7b15mcvCHHY6JOE6/8P1aCvgp1zoa8QJAGwRJb3rW6Lst+m yyEtbzBM2Tul8PRFIHUP5DJ1uFCFwnVfr07rB00lwTqHebRoqw6tZyuMkvJ/jeyarM rZBO/DiU4+B0CtJk2W0XvxwMkVGrlFK4GG+5Bo8Dj1H5zhCDMjImmJ25+VnuQoybl+ xUDXb4/9Q9tMQ== Received: from policy02-mors.netcup.net (unknown [46.38.225.35]) by mors-relay8204.netcup.net (Postfix) with ESMTPS id 4gvZj30ny2z8n0L; Tue, 7 Jul 2026 08:51:51 +0000 (UTC) Received: from mxe9fb.netcup.net (unknown [10.243.12.53]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by policy02-mors.netcup.net (Postfix) with ESMTPS id 4gvZj157qlz8sWT; Tue, 7 Jul 2026 10:51:49 +0200 (CEST) Received: from [IPV6:2a02:8108:8984:1d00:a0cf:1912:4be:477f] (unknown [IPv6:2a02:8108:8984:1d00:a0cf:1912:4be:477f]) by mxe9fb.netcup.net (Postfix) with ESMTPSA id C679A5FC3F; Tue, 7 Jul 2026 10:51:48 +0200 (CEST) Authentication-Results: mxe9fb; spf=pass (sender IP is 2a02:8108:8984:1d00:a0cf:1912:4be:477f) smtp.mailfrom=regressions@leemhuis.info smtp.helo=[IPV6:2a02:8108:8984:1d00:a0cf:1912:4be:477f] Received-SPF: pass (mxe9fb: connection is authenticated) Message-ID: <84233951-ee22-4980-9f17-2af1df51fdbf@leemhuis.info> Date: Tue, 7 Jul 2026 10:51:47 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/mediatek: mtk_dsi: enable hs clock during pre-enable To: =?UTF-8?B?Q0sgSHUgKOiDoeS/iuWFiSk=?= , "me@adamthiede.com" , "bisson.gary@gmail.com" Cc: "chunkuang.hu@kernel.org" , "simona@ffwll.ch" , "dri-devel@lists.freedesktop.org" , AngeloGioacchino Del Regno , "airlied@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "p.zabel@pengutronix.de" , "matthias.bgg@gmail.com" , "linux-mediatek@lists.infradead.org" , "regressions@lists.linux.dev" References: <20260120-mtkdsi-v1-1-b0f4094f3ac3@gmail.com> <42607fa4-485d-4142-b31c-7bfac71118d2@adamthiede.com> <5baeb90d2c3736df67ad075ede4ac765bfeaed2d.camel@mediatek.com> From: Thorsten Leemhuis Content-Language: de-DE, en-US In-Reply-To: <5baeb90d2c3736df67ad075ede4ac765bfeaed2d.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-PPP-Message-ID: <178341430939.3962464.17635774890868316574@mxe9fb.netcup.net> X-NC-CID: zdu5T8PV57LkUnyRdE7oTK/+a14nrtefMRsTmliu6xJM4NY6kzM= On 7/7/26 04:20, CK Hu (胡俊光) wrote: > On Mon, 2026-07-06 at 12:16 +0200, Thorsten Leemhuis wrote: >> On 6/22/26 15:23, Adam Thiede wrote: >> > On 6/22/26 06:22, Gary Bisson wrote: >> > > On Thu, Jun 18, 2026 at 04:06:28PM -0500, Adam Thiede wrote: >> > > > On 1/20/26 05:36, Gary Bisson wrote: >> > > > > Some bridges, such as the TI SN65DSI83, require the HS clock to be >> > > > > running in order to lock its PLL during its own pre-enable function. >> > > > > >> > > > > Without this change, the bridge gives the following error: >> > > > > sn65dsi83 14-002c: failed to lock PLL, ret=-110 >> > > > > sn65dsi83 14-002c: Unexpected link status 0x01 >> > > > > sn65dsi83 14-002c: reset the pipe >> > > > > [...] >> > > > >> > > > This commit was part of 7.1 and caused a problem for me. >> > > > I'm running postmarketOS (basically Alpine Linux) on a Lenovo C330 >> > > > chromebook with a Mediatek MT8173 processor. >> > > > The problem: when the display on my laptop powers off (via suspend or >> > > > idle, >> > > > like xset dpms off) the picture does not come back when the display >> > > > powers >> > > > back on (from resume). The display backlight comes on and brightness is >> > > > adjustable but there is no picture. The only fix is to reboot. >> > > > >> > > > Reverting this commit and applying it as a patch on top of 7.1 >> > > > addresses the >> > > > issue for me. >> > > > >> > > > You can view the config I'm using here: >> > > > https://urldefense.com/v3/__https://gitlab.postmarketos.org/postmarketOS/pmaports/-/__;!!CTRNKA9wMg0ARbw!jrsPDtSEUdaINzLlq92Li8gmsEBkTOxZ6WUzNHjvIN6CyOJjHiHkNSOhIRPXFTLPlaYlxU2uvryVkwjUAN9bmax5$ >> > > > merge_requests/8819 >> > > > >> > > > Is there any sort of testing or other debugging info I can provide to >> > > > help >> > > > address this issue? >> > > >> > > Thanks for reporting the issue, could you share some logs? Is the driver >> > > saying anything during resume? Also, what type of panel is used on that >> > > chromebook? >> > >> > The curious thing is that there are no real logs in dmesg or /var/log/ >> > messages about this. This picture just fails to come back. If there are >> > some kernel params I can set to get deeper logging, that would help, but >> > I'm not aware of any. >> > >> > I think the panel is a "BOE NV116WHM-T00" - I used this command to get >> > info: cat /sys/class/drm/card0-eDP-1/edid | edid-decode >> > >> > Output: https://urldefense.com/v3/__https://termbin.com/8nbd__;!!CTRNKA9wMg0ARbw!jrsPDtSEUdaINzLlq92Li8gmsEBkTOxZ6WUzNHjvIN6CyOJjHiHkNSOhIRPXFTLPlaYlxU2uvryVkwjUAJooSyqL$ >> >> This looked stalled. If I'm mistaken here, please let me known; but if >> no solution is in sight, should we maybe just revert the change until a >> proper was found? > > It's welcome anyone to provide a revert patch, > but I would still wait for the fixup patch until 7.2-rc4. > If no fixup patch exist, then apply the revert patch. >From my understanding of things the position in the devel cycle doesn't matter much in a case like this. To quote Linus statements from https://www.kernel.org/doc/html/latest/process/handling-regressions.html#on-how-quickly-regressions-should-be-fixed """ >From 2026-01-22: But a user complaining should basically result in an immediate fix - possibly a "revert and rethink". With a later clarification on 2026-01-28: It's also worth noting that "immediate" obviously doesn't mean "right this *second* when the problem has been reported". But if it's a regression with a known commit that caused it, I think the rule of thumb should generally be "within a week", preferably before the next rc. """ Adam reported the problem about three weeks ago, so we are way past the "rule of thumb" timeframe Linus set. Ciao, Thorsten