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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEFC5C43331 for ; Mon, 30 Mar 2020 03:31:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BCBEA20733 for ; Mon, 30 Mar 2020 03:31:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Cg/JgVh6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729146AbgC3DbJ (ORCPT ); Sun, 29 Mar 2020 23:31:09 -0400 Received: from mail-pj1-f65.google.com ([209.85.216.65]:52170 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728107AbgC3DbI (ORCPT ); Sun, 29 Mar 2020 23:31:08 -0400 Received: by mail-pj1-f65.google.com with SMTP id w9so6974297pjh.1 for ; Sun, 29 Mar 2020 20:31:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=otJu+eX4lgoyY7c5aWHtihsc0UqeTjjXfeFh1YkhPAI=; b=Cg/JgVh6ZFguiHH+MX9rN4p9sfqLyGbfezUgcNzj3PHFsHNEPTJ4eDqohWJ4ix+cfq 86+xeolceCPoieZ4AwmrsKl0k1viscu053//IHabzLzbRgGRuwz91UWfge1NA1kJpPAt OiZauC4SIqmZg5wDrWWvMU7VzLEFI5QSSin7xgcZzrr7Mzldg1WsAULMQgHJrduk1ghb EbatZdXWg6ONHp3dbk5q8xho6821nsd06f1nVuq551l4cNjiHs8zJsBEE13n0Sqk/yGW 9KqSIFtcbBBlsAuKvBrpmEgSusp0QN9PJPC8yZY6Cbjb7LaTPE12iGjL5Razi2DAmK+B Dblg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=otJu+eX4lgoyY7c5aWHtihsc0UqeTjjXfeFh1YkhPAI=; b=PBG20AFVNrm9jaFRWvoG3RMDmTuKmZA+s8oR+TI82GZ7PT+OiZ2OZ3GOAIsg5DOr8A CY7isWCSmiwwNX4pHCfhBo9UxZmwYfJDEvrfGdMSFcXs8qG/01sdRHupb510IJFSSSoR RtR38BKsEWChTkFhTuSqCIMmxiDCrA600K8yXXslDMK2ZCgr7J8gLZoSbvBXU6ene3jP a1WSWWm47cIYHCaSotfjmrxn6rJ801hFrd1IjpTwHvVSG/oaKICRbkHJz5BkJ3aXl26W 2ibEqPp9dHm3YD4NJgR50/lri8RuVySgAauULecb1dhurUOIqKyottDJDq/zR+zsdpPf fuSw== X-Gm-Message-State: AGi0PubD+GjzHz6qEm3OqAOmTlrCqWYkf1TyFjnxFbG1nEPF5AjMiPbO 8sWRxzpQNFpbpZcSbJ/9J2ljmzHd X-Google-Smtp-Source: APiQypLx8oHfbCFmO4ZmoFs0bDixro1EhUtuQnWSXNZzicy+ylzwCez86O6anrnKbIzQEyN3nR61jw== X-Received: by 2002:a17:90a:77c7:: with SMTP id e7mr1907667pjs.100.1585539067134; Sun, 29 Mar 2020 20:31:07 -0700 (PDT) Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id y193sm8512447pgd.87.2020.03.29.20.31.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Mar 2020 20:31:06 -0700 (PDT) From: Sultan Alsawaf X-Google-Original-From: Sultan Alsawaf To: stable@vger.kernel.org Cc: Sultan Alsawaf Subject: [PATCH 0/2] A couple of important fixes for i915 on 5.4 Date: Sun, 29 Mar 2020 20:30:55 -0700 Message-Id: <20200330033057.2629052-1-sultan@kerneltoast.com> X-Mailer: git-send-email 2.26.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sultan Alsawaf Hi, This patchset contains fixes for two pesky i915 bugs that exist in 5.4. The first bug, fixed by "drm/i915/gt: Schedule request retirement when timeline idles" upstream, is very high power consumption by i915 hardware due to an old commit that broke the RC6 power state for the iGPU on Skylake+. On my laptop, a Dell Precision 5540 with an i9-9880H, the idle power consumption of my laptop with this commit goes down from 10 W to 2 W, saving a massive 8 W of power. On other Skylake+ laptops I tested, this commit reduced idle power consumption by at least a few watts. The difference in power consumption can be observed by running `powertop` while disconnected from the charger, or by using the intel-undervolt tool [1] and running `intel-undervolt measure` which doesn't require being disconnected from the charger. The psys measurement from intel-undervolt is the one of interest. Backporting this commit was not trivial due to i915's high rate of churn, but the backport didn't require changing any code from the original commit; it only required moving code around and not altering some #includes. The second bug causes severe graphical corruption and flickering on laptops which support an esoteric power-saving mechanism called Panel Self Refresh (PSR). Enabled by default in 5.0, PSR causes graphical corruption to the point of unusability on many Dell laptops made within the past few years, since they typically support PSR. A bug was filed with Intel a while ago for this with more information [2]. I suspect most the community hasn't been affected by this bug because ThinkPads and many other laptops I checked didn't support PSR. As of writing, the issues I observed with PSR are fixed in Intel's drm-tip branch, but i915 suffers from so much churn that backporting the individual PSR fixes is infeasible (and an Intel engineer attested to this, saying that the PSR fixes in drm-tip wouldn't be backported [3]). Disabling PSR by default brings us back to pre-5.0 behavior, and from my tests with functional PSR in the drm-tip kernel, I didn't observe any reduction in power consumption with PSR enabled, so there isn't much lost from turning it off. Also, Ubuntu now ships with PSR disabled by default in its affected kernels, so there is distro support behind this change. Thanks, Sultan [1] https://github.com/kitsunyan/intel-undervolt [2] https://gitlab.freedesktop.org/drm/intel/issues/425 [3] https://gitlab.freedesktop.org/drm/intel/issues/425#note_416130 Chris Wilson (1): drm/i915/gt: Schedule request retirement when timeline idles Sultan Alsawaf (1): drm/i915: Disable Panel Self Refresh (PSR) by default drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 + drivers/gpu/drm/i915/gt/intel_engine_types.h | 8 ++ drivers/gpu/drm/i915/gt/intel_lrc.c | 8 ++ drivers/gpu/drm/i915/gt/intel_timeline.c | 1 + .../gpu/drm/i915/gt/intel_timeline_types.h | 3 + drivers/gpu/drm/i915/i915_params.c | 3 +- drivers/gpu/drm/i915/i915_params.h | 2 +- drivers/gpu/drm/i915/i915_request.c | 73 +++++++++++++++++++ drivers/gpu/drm/i915/i915_request.h | 4 + 9 files changed, 101 insertions(+), 3 deletions(-) -- 2.26.0 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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DA2FC2D0F3 for ; Tue, 31 Mar 2020 07:38:28 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 0E1272072A for ; Tue, 31 Mar 2020 07:38:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E1272072A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kerneltoast.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A15596E598; Tue, 31 Mar 2020 07:38:02 +0000 (UTC) Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id 037906E160; Mon, 30 Mar 2020 16:08:33 +0000 (UTC) Received: by mail-pf1-f194.google.com with SMTP id 23so8824989pfj.1; Mon, 30 Mar 2020 09:08:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:resent-from:resent-date:resent-message-id :resent-to:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=otJu+eX4lgoyY7c5aWHtihsc0UqeTjjXfeFh1YkhPAI=; b=Ir7pgl4XmClna7cUx96hBHuHNDzL1t4ysmX7aw+6S9+7Xo0GcLS3+DhjBYFPVucnWt 4boW5Bdxy4K3zZUcy7DvwLQXL75/G0JMcMY684Ho8FGH5OqY4ZXDiavPlqBqShYl7fx6 JWcbzdWijfmg8HOl3BKkhTu1JuU8WGBok/QCaJw38AwLAxu7pxVtXfqrNO3z4sbnO7Sq zMZ2a+wxV5kBOuhn3SHyUpZvmvv+/s3FuopQGuY9SJfbVPkAZQU70EFXIkgdDWMt8Uiw jrzO8XLCsRlO8fF5WcnKUJjEvvWK22J79VFXRgHTj6HYzH5OKzWOPBhfhTMgMH96KXaH U+/Q== X-Gm-Message-State: ANhLgQ1mtEamoQbmuZlWOedgauErYYDIm4RiVfueNN/f7zHlOgF84W3Z skss5248O7SIBtuBR5LQ+tSMP1vX X-Google-Smtp-Source: ADFU+vtUqHNgjuHOAKf/E0Ylxd0QWmsVaQoUTr55SFrii17iNHElhjHR64vWnr73zuWsBWm8rCVwLQ== X-Received: by 2002:a65:6712:: with SMTP id u18mr13576601pgf.93.1585584513343; Mon, 30 Mar 2020 09:08:33 -0700 (PDT) Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id z30sm10492071pfq.84.2020.03.30.09.08.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2020 09:08:32 -0700 (PDT) Resent-From: Sultan Alsawaf Resent-Date: Mon, 30 Mar 2020 09:08:29 -0700 Resent-Message-ID: <20200330160829.GA3400@sultan-box.localdomain> Resent-To: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , Chris Wilson , Tvrtko Ursulin , Mika Kuoppala , Daniele Ceraolo Spurio , Matthew Auld , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id y193sm8512447pgd.87.2020.03.29.20.31.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Mar 2020 20:31:06 -0700 (PDT) From: Sultan Alsawaf X-Google-Original-From: Sultan Alsawaf To: stable@vger.kernel.org Subject: [PATCH 0/2] A couple of important fixes for i915 on 5.4 Date: Sun, 29 Mar 2020 20:30:55 -0700 Message-Id: <20200330033057.2629052-1-sultan@kerneltoast.com> X-Mailer: git-send-email 2.26.0 MIME-Version: 1.0 X-Mailman-Approved-At: Tue, 31 Mar 2020 07:37:59 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sultan Alsawaf Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Sultan Alsawaf Hi, This patchset contains fixes for two pesky i915 bugs that exist in 5.4. The first bug, fixed by "drm/i915/gt: Schedule request retirement when timeline idles" upstream, is very high power consumption by i915 hardware due to an old commit that broke the RC6 power state for the iGPU on Skylake+. On my laptop, a Dell Precision 5540 with an i9-9880H, the idle power consumption of my laptop with this commit goes down from 10 W to 2 W, saving a massive 8 W of power. On other Skylake+ laptops I tested, this commit reduced idle power consumption by at least a few watts. The difference in power consumption can be observed by running `powertop` while disconnected from the charger, or by using the intel-undervolt tool [1] and running `intel-undervolt measure` which doesn't require being disconnected from the charger. The psys measurement from intel-undervolt is the one of interest. Backporting this commit was not trivial due to i915's high rate of churn, but the backport didn't require changing any code from the original commit; it only required moving code around and not altering some #includes. The second bug causes severe graphical corruption and flickering on laptops which support an esoteric power-saving mechanism called Panel Self Refresh (PSR). Enabled by default in 5.0, PSR causes graphical corruption to the point of unusability on many Dell laptops made within the past few years, since they typically support PSR. A bug was filed with Intel a while ago for this with more information [2]. I suspect most the community hasn't been affected by this bug because ThinkPads and many other laptops I checked didn't support PSR. As of writing, the issues I observed with PSR are fixed in Intel's drm-tip branch, but i915 suffers from so much churn that backporting the individual PSR fixes is infeasible (and an Intel engineer attested to this, saying that the PSR fixes in drm-tip wouldn't be backported [3]). Disabling PSR by default brings us back to pre-5.0 behavior, and from my tests with functional PSR in the drm-tip kernel, I didn't observe any reduction in power consumption with PSR enabled, so there isn't much lost from turning it off. Also, Ubuntu now ships with PSR disabled by default in its affected kernels, so there is distro support behind this change. Thanks, Sultan [1] https://github.com/kitsunyan/intel-undervolt [2] https://gitlab.freedesktop.org/drm/intel/issues/425 [3] https://gitlab.freedesktop.org/drm/intel/issues/425#note_416130 Chris Wilson (1): drm/i915/gt: Schedule request retirement when timeline idles Sultan Alsawaf (1): drm/i915: Disable Panel Self Refresh (PSR) by default drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 + drivers/gpu/drm/i915/gt/intel_engine_types.h | 8 ++ drivers/gpu/drm/i915/gt/intel_lrc.c | 8 ++ drivers/gpu/drm/i915/gt/intel_timeline.c | 1 + .../gpu/drm/i915/gt/intel_timeline_types.h | 3 + drivers/gpu/drm/i915/i915_params.c | 3 +- drivers/gpu/drm/i915/i915_params.h | 2 +- drivers/gpu/drm/i915/i915_request.c | 73 +++++++++++++++++++ drivers/gpu/drm/i915/i915_request.h | 4 + 9 files changed, 101 insertions(+), 3 deletions(-) -- 2.26.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19869C2D0F1 for ; Mon, 30 Mar 2020 21:04:23 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id EDB8B20714 for ; Mon, 30 Mar 2020 21:04:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EDB8B20714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kerneltoast.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 21B2F6E4A7; Mon, 30 Mar 2020 21:04:22 +0000 (UTC) Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id 037906E160; Mon, 30 Mar 2020 16:08:33 +0000 (UTC) Received: by mail-pf1-f194.google.com with SMTP id 23so8824989pfj.1; Mon, 30 Mar 2020 09:08:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:resent-from:resent-date:resent-message-id :resent-to:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=otJu+eX4lgoyY7c5aWHtihsc0UqeTjjXfeFh1YkhPAI=; b=Ir7pgl4XmClna7cUx96hBHuHNDzL1t4ysmX7aw+6S9+7Xo0GcLS3+DhjBYFPVucnWt 4boW5Bdxy4K3zZUcy7DvwLQXL75/G0JMcMY684Ho8FGH5OqY4ZXDiavPlqBqShYl7fx6 JWcbzdWijfmg8HOl3BKkhTu1JuU8WGBok/QCaJw38AwLAxu7pxVtXfqrNO3z4sbnO7Sq zMZ2a+wxV5kBOuhn3SHyUpZvmvv+/s3FuopQGuY9SJfbVPkAZQU70EFXIkgdDWMt8Uiw jrzO8XLCsRlO8fF5WcnKUJjEvvWK22J79VFXRgHTj6HYzH5OKzWOPBhfhTMgMH96KXaH U+/Q== X-Gm-Message-State: ANhLgQ1mtEamoQbmuZlWOedgauErYYDIm4RiVfueNN/f7zHlOgF84W3Z skss5248O7SIBtuBR5LQ+tSMP1vX X-Google-Smtp-Source: ADFU+vtUqHNgjuHOAKf/E0Ylxd0QWmsVaQoUTr55SFrii17iNHElhjHR64vWnr73zuWsBWm8rCVwLQ== X-Received: by 2002:a65:6712:: with SMTP id u18mr13576601pgf.93.1585584513343; Mon, 30 Mar 2020 09:08:33 -0700 (PDT) Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id z30sm10492071pfq.84.2020.03.30.09.08.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2020 09:08:32 -0700 (PDT) Resent-From: Sultan Alsawaf Resent-Date: Mon, 30 Mar 2020 09:08:29 -0700 Resent-Message-ID: <20200330160829.GA3400@sultan-box.localdomain> Resent-To: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , Chris Wilson , Tvrtko Ursulin , Mika Kuoppala , Daniele Ceraolo Spurio , Matthew Auld , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id y193sm8512447pgd.87.2020.03.29.20.31.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Mar 2020 20:31:06 -0700 (PDT) From: Sultan Alsawaf X-Google-Original-From: Sultan Alsawaf To: stable@vger.kernel.org Date: Sun, 29 Mar 2020 20:30:55 -0700 Message-Id: <20200330033057.2629052-1-sultan@kerneltoast.com> X-Mailer: git-send-email 2.26.0 MIME-Version: 1.0 X-Mailman-Approved-At: Mon, 30 Mar 2020 21:04:09 +0000 Subject: [Intel-gfx] [PATCH 0/2] A couple of important fixes for i915 on 5.4 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: , Cc: Sultan Alsawaf Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Sultan Alsawaf Hi, This patchset contains fixes for two pesky i915 bugs that exist in 5.4. The first bug, fixed by "drm/i915/gt: Schedule request retirement when timeline idles" upstream, is very high power consumption by i915 hardware due to an old commit that broke the RC6 power state for the iGPU on Skylake+. On my laptop, a Dell Precision 5540 with an i9-9880H, the idle power consumption of my laptop with this commit goes down from 10 W to 2 W, saving a massive 8 W of power. On other Skylake+ laptops I tested, this commit reduced idle power consumption by at least a few watts. The difference in power consumption can be observed by running `powertop` while disconnected from the charger, or by using the intel-undervolt tool [1] and running `intel-undervolt measure` which doesn't require being disconnected from the charger. The psys measurement from intel-undervolt is the one of interest. Backporting this commit was not trivial due to i915's high rate of churn, but the backport didn't require changing any code from the original commit; it only required moving code around and not altering some #includes. The second bug causes severe graphical corruption and flickering on laptops which support an esoteric power-saving mechanism called Panel Self Refresh (PSR). Enabled by default in 5.0, PSR causes graphical corruption to the point of unusability on many Dell laptops made within the past few years, since they typically support PSR. A bug was filed with Intel a while ago for this with more information [2]. I suspect most the community hasn't been affected by this bug because ThinkPads and many other laptops I checked didn't support PSR. As of writing, the issues I observed with PSR are fixed in Intel's drm-tip branch, but i915 suffers from so much churn that backporting the individual PSR fixes is infeasible (and an Intel engineer attested to this, saying that the PSR fixes in drm-tip wouldn't be backported [3]). Disabling PSR by default brings us back to pre-5.0 behavior, and from my tests with functional PSR in the drm-tip kernel, I didn't observe any reduction in power consumption with PSR enabled, so there isn't much lost from turning it off. Also, Ubuntu now ships with PSR disabled by default in its affected kernels, so there is distro support behind this change. Thanks, Sultan [1] https://github.com/kitsunyan/intel-undervolt [2] https://gitlab.freedesktop.org/drm/intel/issues/425 [3] https://gitlab.freedesktop.org/drm/intel/issues/425#note_416130 Chris Wilson (1): drm/i915/gt: Schedule request retirement when timeline idles Sultan Alsawaf (1): drm/i915: Disable Panel Self Refresh (PSR) by default drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 + drivers/gpu/drm/i915/gt/intel_engine_types.h | 8 ++ drivers/gpu/drm/i915/gt/intel_lrc.c | 8 ++ drivers/gpu/drm/i915/gt/intel_timeline.c | 1 + .../gpu/drm/i915/gt/intel_timeline_types.h | 3 + drivers/gpu/drm/i915/i915_params.c | 3 +- drivers/gpu/drm/i915/i915_params.h | 2 +- drivers/gpu/drm/i915/i915_request.c | 73 +++++++++++++++++++ drivers/gpu/drm/i915/i915_request.h | 4 + 9 files changed, 101 insertions(+), 3 deletions(-) -- 2.26.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx