From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7F686C021B3 for ; Thu, 20 Feb 2025 10:00:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C7CCC10E903; Thu, 20 Feb 2025 10:00:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; secure) header.d=ffwll.ch header.i=@ffwll.ch header.b="S3knFB8T"; dkim-atps=neutral Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0AEBD10E903 for ; Thu, 20 Feb 2025 10:00:32 +0000 (UTC) Received: by mail-wm1-f47.google.com with SMTP id 5b1f17b1804b1-4394a0c65fcso6645185e9.1 for ; Thu, 20 Feb 2025 02:00:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; t=1740045631; x=1740650431; darn=lists.freedesktop.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=7gSnEulNPHGW59kN5NlhcVPq1odJotXpIwPfOlH4gXc=; b=S3knFB8T4eP6lKUsPhz10JKwbO8pl1ONqjSWd1mvZv9wzBMHkOrjsBnZnsLAqOOQYc 6IG055qZMwqDrCYw7tXUMcObqhYBzzyiHIXVM+uXyxmRy7xwerX9AS9OHJ4ipm4+dTDK 3C1tRPOaBwe+33Na3B7voTPR7qmWSGFvEYSDA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740045631; x=1740650431; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7gSnEulNPHGW59kN5NlhcVPq1odJotXpIwPfOlH4gXc=; b=KFmnftjzvV92wQ6O1fDiH9Tj4hbY6poR0ALNSKH7SKk6t/Ld8MxlmtnuMdjDzvf9Qc Iu5L/AhgpEQd4nicOxK9VxD1bbRDPzXEdXyqorbTUJWw5nFWso9dBkYMi/oDaBIHkJIF s0IXH4/6eHyyAg8ftlpPtdvWtVCUyIK51VQVUDHbcrqy3Op/ix89/ZhNarHKULNuFuCe 3sNaBjLN0Hahz2NNU+XeRRaR99FPNI1kpLq1TD3l0o21Eb1H2wIy1l2HWGm2kYO/XVOL EI+0zk7YF3tA9tWmCAEOcU4ni7tUzA6Mzpa84v4MEMQ92KsIjw/m+Df9vLXbX1bWYgLB W0gA== X-Forwarded-Encrypted: i=1; AJvYcCVOKT46TrE/jG5VbZ4s/Z+7IdLVLP3NzPYF/YnpvXcukp8O3wrdzw4TPPyLEc8wzLY4491OzG8FUuM=@lists.freedesktop.org X-Gm-Message-State: AOJu0YxyE15bFsBFqjHaQAbX7hhMRpHbnWWLRR2sZhe6XMErdx0LkhU9 04Ilqk3w7UN4Ci+JhvjsuChlZMhEO4kAeQXORAXa/8xfY31bkVwYcxcMqTpeuX4= X-Gm-Gg: ASbGncupx1YdEqgeApiD5AxWm7kZBXzd8PADfe6zIz0XCDFffcXUxEQOEcfz69rO4Qh 454372aYSzgJPKbnPxtTBZhti9+4YqB0bOlYKgcJleieaMSbI/V4FigiMUMXOWvshFOwLNcexY/ V177O+EFO8Hmddh+T6cRg5w2z3VEKKUSIrtXOSdh0EwEcIf63gV5TC1TszSs8dK+0I/jGw9ffTf jq9gnJnNPrIpxU7G1vIjH8zAHqcIbUZE4V2PecVMt5NnnRB42p5XnVWfGWj8qy55RHa6PpX3AEU L9Vwn+0j/03S2/Lxgp6dDGR5YGQ= X-Google-Smtp-Source: AGHT+IH6VXFG7I7YI20n9sEVCzM1EqLuDUUlC7OOJg5EJY1l1IPCAZhZ9KqyfSoBugjctrkmj3Gb/w== X-Received: by 2002:a05:600c:4e87:b0:439:9274:81cd with SMTP id 5b1f17b1804b1-439927484b2mr113239115e9.4.1740045631154; Thu, 20 Feb 2025 02:00:31 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:5485:d4b2:c087:b497]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4399d55fc1asm38775925e9.35.2025.02.20.02.00.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2025 02:00:30 -0800 (PST) Date: Thu, 20 Feb 2025 11:00:28 +0100 From: Simona Vetter To: Ville Syrjala Cc: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Subject: Re: [PATCH] drm/atomic: Filter out redundant DPMS calls Message-ID: References: <20250219160239.17502-1-ville.syrjala@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Operating-System: Linux phenom 6.12.11-amd64 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Feb 20, 2025 at 10:53:57AM +0100, Simona Vetter wrote: > On Wed, Feb 19, 2025 at 06:02:39PM +0200, Ville Syrjala wrote: > > From: Ville Syrjälä > > > > Video players (eg. mpv) do periodic XResetScreenSaver() calls to > > keep the screen on while the video playing. The modesetting ddx > > plumbs these straight through into the kernel as DPMS setproperty > > ioctls, without any filtering whatsoever. When implemented via > > atomic these end up as full commits on the crtc, which leads to a > > dropped frame every time XResetScreenSaver() is called. > > I think you should add here that it's just an empty commit, because we do > filter out redundant commits where crtc->active_changed does nothing. > Except we still run the entire machinery with timestamps and drm_event and > everything. > > And I don't think it's worth to filter that out at the atomic level, > because it's really only legacy ioctl that had this "complete noop" > behaviour. > > With the commit message augmented: > > Reviewed-by: Simona Vetter Ok, one more thing: Please also augment the dpms property uapi doc text with a note that we make this guarantee. Otherwise this feels a bit too much opaque magic. Maybe even a one-liner comment in the code that this is uapi? -Sima > > Might also be nice to have a igt for this? Plus also wondering whether we > should cc: stable it. > > Cheers, Sima > > > Let's just filter out redundant DPMS property changes in the > > kernel to avoid this issue. > > > > Signed-off-by: Ville Syrjälä > > --- > > drivers/gpu/drm/drm_atomic_uapi.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c > > index 2765ba90ad8f..c2726af6698e 100644 > > --- a/drivers/gpu/drm/drm_atomic_uapi.c > > +++ b/drivers/gpu/drm/drm_atomic_uapi.c > > @@ -957,6 +957,10 @@ int drm_atomic_connector_commit_dpms(struct drm_atomic_state *state, > > > > if (mode != DRM_MODE_DPMS_ON) > > mode = DRM_MODE_DPMS_OFF; > > + > > + if (connector->dpms == mode) > > + goto out; > > + > > connector->dpms = mode; > > > > crtc = connector->state->crtc; > > -- > > 2.45.3 > > > > -- > Simona Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch -- Simona Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch