From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-103.mailbox.org (mout-p-103.mailbox.org [80.241.56.161]) (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 308F8305E2E for ; Thu, 29 Jan 2026 10:06:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.161 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769681196; cv=none; b=iuX43WeDfLS8KwL93JyZMvNCC2ju4qDiCCH+9O8fydr7NuDOhPBalfxluSeO63p7Be0YV+4LtQbSCWMNFCiaA4dwdIj837xCYTxm4Vlni68B6L/95065Yduxoqtso/9OxhW8SPfmjY3AoC46ZMSSlrYmFqv3AnVmsmFE8KGLLnI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769681196; c=relaxed/simple; bh=2KFZ8rerGKiDYMpOOT/9bqox/TVTYFFuv+tsEyIpdCM=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=FY6knE6XY5iftlVkvdU9bdkXfHQx6+cJCgWcjy5tgJ4HKVgvpfZrubR2HqW0aUbJgOsXE7x3pa9iFssFtrwHAe3ZL7pQJRV7z/ztSYbqHcbeKHqXATKQHnsjhM5mlzEudMKVDpgF0VHgau1gHHOUozsoOc+hlKNRIaZDbxHvmQE= 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=rCBeFohe; arc=none smtp.client-ip=80.241.56.161 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="rCBeFohe" Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:b231:465::2]) (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-103.mailbox.org (Postfix) with ESMTPS id 4f1vtR3CF4z9tpy; Thu, 29 Jan 2026 11:06:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1769681183; 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=Kb2jfGjQwA7ut3j/ptuhkH0E+7WJpvt3WXc+5hh8JZk=; b=rCBeFohevPYC91yLLM30we8BcEI/k5LIzBNrk35/oVkA1PJ6KKSG26TBpXAvr9GhRDSvww BRk5fVRZMN29nF8AtDDeKZ9KM84kM39F5niIxK6l9ix8H6OBwffUwao5Jeehvja8Q1q5aC iQ3GPYl0WPeqdyBDKqdOXLYpjHhljMRqji8/WIJkOZZA61ZPVPCPOJ5uImYZcnFQMM3D0S K2Cr03/+kdy9hZqYKGgJeB9MN3FpQcdCU1c/CM1qhCLmQSoEKlNqZRfA6+DFbeUC9FFnJ0 pwBW+RuArlxw0v3sFVaZm49t15STwXQrqNf9hMBz0HXhf7OJEH3k8vOCqvhwcg== Message-ID: <6f1239d2-eec3-40b6-aca7-5b278350dd04@mailbox.org> Date: Thu, 29 Jan 2026 11:06:11 +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() From: =?UTF-8?Q?Michel_D=C3=A4nzer?= To: =?UTF-8?Q?Christian_K=C3=B6nig?= , =?UTF-8?Q?Timur_Krist=C3=B3f?= , Alex Deucher , Hamza Mahfooz Cc: Mario Limonciello , 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 , Fangzhi Zuo , amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260123000537.2450496-1-someguy@effective-light.com> <17cd6378-e3fa-419b-90d3-7e0549817110@amd.com> <2203806.9o76ZdvQCi@timur-hyperion> Content-Language: en-CA In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-MBO-RS-ID: 5bc67119825c6734ca4 X-MBO-RS-META: f3p4f6ow56ajcedz4stst43zs8fqy943 On 1/28/26 15:25, Michel Dänzer wrote: > On 1/28/26 13:48, Christian König wrote: >> On 1/28/26 13:14, Timur Kristóf wrote: >>> On Wednesday, January 28, 2026 12:26:20 PM Central European Standard Time >>> Michel Dänzer wrote: >>>> On 1/28/26 11:39, Christian König wrote: >>>>> >>>>> 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?). >>> >>> In all the bug reports I've seen about page flip timeouts, and in all the >>> timeouts I've seen on my machine, the screen remains on, but frozen. >>> It doesn't go black and doesn't turn off. >>> >>> Christian, why would the CRTC be turned off? >> >> Exactly that's the question we need to answer. >> >> But from what you describe the CRTC keeps on, just doesn't send any more vblank events. > > The vblank interrupt source getting accidentally disabled might be one possible cause though. Another possibility is that test-only commits with the DRM_MODE_ATOMIC_TEST_ONLY flag (which can happen in parallel while the kernel is processing a "real" commit) accidentally have side effects on the current kernel state, resulting in the "real" commit failing to do something it should. There have been bugs like that in the amdgpu DM code before. Anyway, this is all speculation. Somebody just needs to dig in and get to the bottom of why the commits aren't getting completed. -- Earthling Michel Dänzer \ GNOME / Xwayland / Mesa developer https://redhat.com \ Libre software enthusiast