From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-102.mailbox.org (mout-p-102.mailbox.org [80.241.56.152]) (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 A58A334575A for ; Wed, 28 Jan 2026 11:26:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.152 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769599597; cv=none; b=rqCFdmbPf6xnrIboz+cvG4oBxjIen5i1xv1VcScnlyM6+Bu66ORssGEZpi5VfW/qbZ734q+9TWUa7ZTCCHJh8tDyWXUfMYMVIt/COagCEAOwbnCr46NNoB4FUDBjaS/kVkBp0yEMVn1th1KFYAKAXii7crbiQJTzazpgVpQxG1E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769599597; c=relaxed/simple; bh=Ud3jPXFe5HvquekhtH+UoHlRGKlKOK9qWFSoKD0f6WU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=fSmpWlocdqIS5U00kWUtSPSZS7/K9OGLHC7FCCS0NImou5CbwUyUVWwTrbncpTpf6h27x0RdM+qiLWHcMsv17t5zNlODpsxYo9AJrFuA21smt82fCwqaJOcTEifs12aN6FlWrYMyCba1Mu1uNRR/fCGs5Zi7ykfip5T52gVbwaA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org; spf=pass smtp.mailfrom=mailbox.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b=qJw3Ji5p; arc=none smtp.client-ip=80.241.56.152 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mailbox.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b="qJw3Ji5p" Received: from smtp102.mailbox.org (smtp102.mailbox.org [IPv6:2001:67c:2050:b231:465::102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-102.mailbox.org (Postfix) with ESMTPS id 4f1KjL1TZXz9tmC; Wed, 28 Jan 2026 12:26:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1769599590; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UgMqvRxiMInROhFo09cCsWov6HfEo9x2oEpjYZtqkjM=; b=qJw3Ji5pgV7YO8j2CKYL46Zm0LAnV4tkneRpDowzhJHTQGwgdmeQbV5sSQLu0dxioQjUpI +sqK346GVPrrA9VG4ZfVgyf72EfZvK9mLawealRB6mv6F57eUti8NZlyyEOkgnqK5QNQiB QQjHi6ok6nk5mmikDOYcRT0f0wI2mw6HRdXSAeC7zxqVPv3PZPexM8ay1z7eGUWgUmFKEt vsf14wftsylNXmQV6axEFI/w6zkJoHkjA3YVVGM9gXOb6ai872Yn+ZypRw3vhqkkSofq5q dgu7sjGru+J0zD7pNwk87GYDKQTyf+3PWfhprTnfIIhnwwfOmIOzp+tJYOyi8Q== Message-ID: Date: Wed, 28 Jan 2026 12:26:20 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 1/2] drm: introduce page_flip_timeout() To: =?UTF-8?Q?Christian_K=C3=B6nig?= , Alex Deucher , Hamza Mahfooz Cc: Mario Limonciello , =?UTF-8?Q?Timur_Krist=C3=B3f?= , dri-devel@lists.freedesktop.org, Alex Deucher , David Airlie , Simona Vetter , Harry Wentland , Leo Li , Rodrigo Siqueira , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Sunil Khatri , Ce Sun , Lijo Lazar , Kenneth Feng , Ivan Lipski , Alex Hung , Tom Chung , Melissa Wen , =?UTF-8?Q?Michel_D=C3=A4nzer?= , Fangzhi Zuo , amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260123000537.2450496-1-someguy@effective-light.com> <2de6d428-b997-4ba8-8766-a211e5612e72@amd.com> <2349754.vFx2qVVIhK@timur-hyperion> <17cd6378-e3fa-419b-90d3-7e0549817110@amd.com> From: =?UTF-8?Q?Michel_D=C3=A4nzer?= Content-Language: en-CA In-Reply-To: <17cd6378-e3fa-419b-90d3-7e0549817110@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-MBO-RS-ID: d8bd9bd850864ad67a1 X-MBO-RS-META: a5jk46pmjgbh87au54hpo1sbf1zjj4wd On 1/28/26 11:39, Christian König wrote: > On 1/27/26 23:57, Alex Deucher wrote: >> On Tue, Jan 27, 2026 at 5:53 PM Hamza Mahfooz >> wrote: >>> >>> On Mon, Jan 26, 2026 at 09:20:55AM -0500, Alex Deucher wrote: >>>> I suspect just calling drm_crtc_send_vblank_event() here on the >>>> relevant crtcs would be enough. >>>> >>> >>> Seems like an interesting idea, though I would imagine we would still >>> want to attempt a reset (of some kind) assuming that the subsequent page >>> flip also experiences a timeout. >> >> Is it actually a timeout or just missed interrupts? I'm wondering if >> some power feature races with the modeset and causes the interrupt to >> get missed from time to time. > > That is my strong suspicion as well. > > Even if we missed a vblank interrupt that thing is reoccurring, so the worst thing that can happen is that we delayed reporting back success by one frame. > > So something must have turned the CRTC fully off. Not sure that's a generally valid conclusion (do the gitlab issues talk about the display going black, or about it staying on but freezing?). AFAIR at least in some cases amdgpu uses a dedicated "page flip" interrupt instead of the vblank interrupt, in which case missing a single interrupt could cause a timeout. P.S. Completing the atomic commit and sending the completion event must work even if user space turns off any CRTCs as part of the commit[0]. So your hypothesis would be a kernel bug, accidentally turning off the CRTC and/or not handling a CRTC getting turned off correctly. [0] If any CRTC for which the commit has state is off both before and after the commit though, the commit fails with an error before it could result in a timeout. -- Earthling Michel Dänzer \ GNOME / Xwayland / Mesa developer https://redhat.com \ Libre software enthusiast