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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0EFEC433F5 for ; Thu, 18 Nov 2021 08:34:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B774161423 for ; Thu, 18 Nov 2021 08:34:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244679AbhKRIhk (ORCPT ); Thu, 18 Nov 2021 03:37:40 -0500 Received: from mail-0201.mail-europe.com ([51.77.79.158]:60672 "EHLO mail-0201.mail-europe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244635AbhKRIhW (ORCPT ); Thu, 18 Nov 2021 03:37:22 -0500 Date: Thu, 18 Nov 2021 08:34:15 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=emersion.fr; s=protonmail; t=1637224456; bh=vfacuKJ/8pxBqZYX9U97ETpBAOFypIw5shMz2e4BuQI=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=kEWhhH7ZqAVsnizPbtaisRT0gUjetqk1SpO2vZNn8ngbQP6PcYwPHdenYL62KgZOa yCS0GP6sWd8yuej9AcSZYx3HgY15w0CMC3IAf/an67IxMso4emPR2CcFwKoRsWOc6D JaTefHSzDlzHKWa3A5yaWKoDZg1wzwyesiuKurYxlB98wUrXG7YfoJfaK83XSZaneY zvymOLYwFIdxBFBj490NF1YWmeg8bACUmwnqvfTTdP0Y8x3c41h7Av+uzHdVw8AgwL wqKZdkiaFEB5AuLf5N981PDXuwsF62VOxjKMGC0jawPFOvNtA+3XMSIpFRxlaQjITd 5CiKeDPlSFlhg== To: Brian Norris From: Simon Ser Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , David Airlie , Dmitry Torokhov , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Doug Anderson , linux-rockchip@lists.infradead.org, "Kristian H . Kristensen" , Andrzej Hajda , linux-input@vger.kernel.org, Pekka Paalanen Reply-To: Simon Ser Subject: Re: [PATCH v2 0/2] drm: Support input-boosted panel self-refresh exit Message-ID: In-Reply-To: <20211117224841.3442482-1-briannorris@chromium.org> References: <20211117224841.3442482-1-briannorris@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, >From a user-space point-of-view, we discussed about this patch on IRC a few days ago [1]. Since this adds a policy decision we think it'd be best to al= low user-space to control this behavior. Also cc Pekka. Thanks, Simon [1]: https://oftc.irclog.whitequark.org/dri-devel/2021-11-07#1636276286-163= 6273745; > A variety of applications have found it useful to listen to > user-initiated input events to make decisions within a DRM driver, given > that input events are often the first sign that we're going to start > doing latency-sensitive activities: > > * Panel self-refresh: software-directed self-refresh (e.g., with > Rockchip eDP) is especially latency sensitive. In some cases, it can > take 10s of milliseconds for a panel to exit self-refresh, which can > be noticeable. Rockchip RK3399 Chrome OS systems have always shipped > with an input_handler boost, that preemptively exits self-refresh > whenever there is input activity. > > * GPU drivers: on GPU-accelerated desktop systems, we may need to > render new frames immediately after user activity. Powering up the > GPU can take enough time that it is worthwhile to start this process > as soon as there is input activity. Many Chrome OS systems also ship > with an input_handler boost that powers up the GPU. > > I implement the first bullet in this series, and I also compared with > some out-of-tree patches for the second, to ensure this could be useful > there too. > > Past work on upstreaming a variety of Chromebook display patches got > held up for this particular feature, as there was some desire to make it > a bit more generic, for one. See the latest here: > > https://lore.kernel.org/all/20180405095000.9756-25-enric.balletbo@colla= bora.com/ > [PATCH v6 24/30] drm/rockchip: Disable PSR on input events > > I significantly rewrote this to adapt it to the new common > drm_self_refresh_helpers and to add a new drm_input_helper thin library, > so I only carry my own authorship on this series. > > Admittedly, this "drm_input_helper" library is barely DRM-specific at > all, except that all display- and GPU-related input-watchers are likely > to want to watch similar device behavior (unlike, say, rfkill or led > input_handler code). The approximate consensus so far seems to be that > (a) this isn't much code; if we need it for other subsystems (like, > cpufreq-boost), it's easy to implement similar logic > (b) input subsystem maintainers think the existing input_handler > abstraction is good enough > So, I keep the thin input helper in drivers/gpu/drm/. > > v1: https://lore.kernel.org/all/20211103234018.4009771-1-briannorris@chro= mium.org/ > > Changes in v2: > - Honor CONFIG_INPUT dependency, via new CONFIG_DRM_INPUT_HELPER > - Remove void*; users should use container_of() > - Document the callback context > - Delay PSR re-entry, when already disabled > - Allow default configuration via Kconfig and modparam > - really CC dri-devel@lists.freedesktop.org (oops!) > > Brian Norris (2): > drm/input_helper: Add new input-handling helper > drm/self_refresh: Disable self-refresh on input events > > drivers/gpu/drm/Kconfig | 22 ++++ > drivers/gpu/drm/Makefile | 2 + > drivers/gpu/drm/drm_input_helper.c | 143 ++++++++++++++++++++++ > drivers/gpu/drm/drm_self_refresh_helper.c | 98 ++++++++++++--- > include/drm/drm_input_helper.h | 41 +++++++ > 5 files changed, 292 insertions(+), 14 deletions(-) > create mode 100644 drivers/gpu/drm/drm_input_helper.c > create mode 100644 include/drm/drm_input_helper.h > > -- > 2.34.0.rc1.387.gb447b232ab-goog