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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69B9DC433EF for ; Fri, 22 Jul 2022 17:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236143AbiGVRg0 (ORCPT ); Fri, 22 Jul 2022 13:36:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235919AbiGVRgZ (ORCPT ); Fri, 22 Jul 2022 13:36:25 -0400 Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C66DD8F52E for ; Fri, 22 Jul 2022 10:36:23 -0700 (PDT) Received: by mail-wm1-x32e.google.com with SMTP id f24-20020a1cc918000000b003a30178c022so5606663wmb.3 for ; Fri, 22 Jul 2022 10:36:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yGBGk+p2EktzA+zS1mnmSkS2k1FkCaq2TcgNmtHB9w8=; b=AuiC7D3WaG23z3SLsy5dE+QMQxe+snbzEWYetJrnDWtIk5JkMaBzzb+1XmGz/7npeJ prALpI+A0WrXNqQ+ZPXUQxR2/OttVmzrZN8/rQcazbGWI2uVfqAAN2ELkjiPt5lIwNLh jqQoZAjQ1N5+bwAF90E/3eLtTEAb+zMDiqqv0knOHSmuH9tLjhMcuDYYcDbWKtZCZ1d2 KjwZJOyABGNRkacHxap052MwJCkVrWYekdQz/hStIgdovBy7JMUqJEbOtvj0k+ZJeRjo nva1EScC/2J+fRygysf7Z1Kf8dNcietJ9qXqcBUFv0Dph+lQvORTcFYX7w66YyrWpzBk TL2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yGBGk+p2EktzA+zS1mnmSkS2k1FkCaq2TcgNmtHB9w8=; b=eDcMeEJGsgdgYppFnJm/hbFgB4oynveyN9+/2n7cNkCLG2IhxU/eKbeitMUeMT08/9 VIgn+PzM8EvHrp73YVg8WKC/+ge6dMlRTt60nAD4RQ19R08BqIHDexsDqKd9m18TW/Ay iEuFQWmAjSB4XeWGDDIE52VbtvBVQ8s8dy5S9bH8Jj6OfF3W3lvWKww9IAYOPQWCb1RK NW8qy5Ux2vTMFjoFU7FduuCd8haXxyAo3Ruou6d2nAGpnV9VqczNXW+2ZCV/lkdA6eD0 KNHZkscuITQzsrAVJmUR+QF/IXLffQ0u+wckmvxXZ4aU7y6oCWmpNWfGdb609dUXxUSn o9uA== X-Gm-Message-State: AJIora+HtRFticTEJ2XFfk4+A/PR5JPr5KDnxHGnCW1S9VWzAi53ALru Hw9G9cnAoc2PkkazzToHAGKCnNm0HgvHWwJ1yMn2DGp1 X-Google-Smtp-Source: AGRyM1u39p8LsNLN5QDBQqApbbnXq6QehY4cZtGOoda3GVQm5WQIb47ThAB08yL1BKFo1IzMvE0TGABxt/gg8mQM5u0= X-Received: by 2002:a05:600c:3510:b0:3a3:34e7:cfc8 with SMTP id h16-20020a05600c351000b003a334e7cfc8mr6773219wmq.164.1658511382374; Fri, 22 Jul 2022 10:36:22 -0700 (PDT) MIME-Version: 1.0 References: <20220721152314.RFC.1.Ie333b3e4aff6e4a5b58c4aa805e030e561be8773@changeid> <269f2610-425b-f296-dcfc-89bdc2e1d587@quicinc.com> In-Reply-To: From: Rob Clark Date: Fri, 22 Jul 2022 10:36:44 -0700 Message-ID: Subject: Re: [RFC PATCH] drm/edid: Make 144 Hz not preferred on Sharp LQ140M1JW46 To: Doug Anderson Cc: Abhinav Kumar , dri-devel , freedreno , Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , LKML , Sankeerth Billakanti Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 22, 2022 at 9:48 AM Doug Anderson wrote: > > Hi, > > On Fri, Jul 22, 2022 at 9:37 AM Abhinav Kumar wrote: > > > > + sankeerth > > > > Hi Doug > > > > On 7/21/2022 3:23 PM, Douglas Anderson wrote: > > > The Sharp LQ140M1JW46 panel is on the Qualcomm sc7280 CRD reference > > > board. This panel supports 144 Hz and 60 Hz. In the EDID, the 144 Hz > > > mode is listed first and thus is marked preferred. The EDID decode I > > > ran says: > > > > > > First detailed timing includes the native pixel format and preferred > > > refresh rate. > > > > > > ... > > > > > > Detailed Timing Descriptors: > > > DTD 1: 1920x1080 143.981 Hz 16:9 166.587 kHz 346.500 MHz > > > Hfront 48 Hsync 32 Hback 80 Hpol N > > > Vfront 3 Vsync 5 Vback 69 Vpol N > > > DTD 2: 1920x1080 59.990 Hz 16:9 69.409 kHz 144.370 MHz > > > Hfront 48 Hsync 32 Hback 80 Hpol N > > > Vfront 3 Vsync 5 Vback 69 Vpol N > > > > > > I'm proposing here that the above is actually a bug and that the 60 Hz > > > mode really should be considered preferred by Linux. > > > > > > The argument here is that this is a laptop panel and on a laptop we > > > know power will always be a concern. Presumably even if someone using > > > this panel wanted to use 144 Hz for some use cases they would only do > > > so dynamically and would still want the default to be 60 Hz. > > > > > > Let's change the default to 60 Hz using a standard quirk. > > > > > > Signed-off-by: Douglas Anderson > > > > Yes, we were aware that 144Hz was getting picked. We found that while > > debugging the screen corruption issue. > > > > Well, yes power would be less with 60Hz but so will be the performance. > > What performance specifically will be less with 60 Hz? In general the > sc7280 CPU is a bit memory-bandwidth constrained and the LCD refresh > from memory is a non-trivial part of that. Reducing to 60 Hz will > relieve some of the memory bandwidth pressure and will actually allow > tasks on the CPU to run _faster_. I guess the downside is that some > animations might be a little less smooth... I guess he is referring to something that is vblank sync'd running faster than 60fps. but OTOH it is a bit of a waste for fbcon to be using 144Hz. And there are enough android games that limit themselves to 30fps to save your "phone" battery. So it seems a lot more sane to default to 60Hz and let userspace that knows it wants more pick the 144Hz rate when needed. BR, -R > > > > The test teams have been validating with 144Hz so far so we are checking > > internally with the team whether its OKAY to goto 60Hz now since that > > kind of invalidates the testing they have been doing. > > You're worried that the panel itself won't work well at 60 Hz, or > something else about the system won't? The whole system in general > needs to work well with 60 Hz displays and I expect them to be much > more common than 144 Hz displays. Quite honestly if switching to 60 Hz > uncovers a problem that would be a huge benefit of landing this patch > because it would mean we'd find it now rather than down the road when > someone hooks up a different panel. > > -Doug 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 0CF20C43334 for ; Fri, 22 Jul 2022 17:36:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 811DC11AE35; Fri, 22 Jul 2022 17:36:27 +0000 (UTC) Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [IPv6:2a00:1450:4864:20::335]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0414911A8AB; Fri, 22 Jul 2022 17:36:23 +0000 (UTC) Received: by mail-wm1-x335.google.com with SMTP id a18-20020a05600c349200b003a30de68697so5406424wmq.0; Fri, 22 Jul 2022 10:36:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yGBGk+p2EktzA+zS1mnmSkS2k1FkCaq2TcgNmtHB9w8=; b=AuiC7D3WaG23z3SLsy5dE+QMQxe+snbzEWYetJrnDWtIk5JkMaBzzb+1XmGz/7npeJ prALpI+A0WrXNqQ+ZPXUQxR2/OttVmzrZN8/rQcazbGWI2uVfqAAN2ELkjiPt5lIwNLh jqQoZAjQ1N5+bwAF90E/3eLtTEAb+zMDiqqv0knOHSmuH9tLjhMcuDYYcDbWKtZCZ1d2 KjwZJOyABGNRkacHxap052MwJCkVrWYekdQz/hStIgdovBy7JMUqJEbOtvj0k+ZJeRjo nva1EScC/2J+fRygysf7Z1Kf8dNcietJ9qXqcBUFv0Dph+lQvORTcFYX7w66YyrWpzBk TL2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yGBGk+p2EktzA+zS1mnmSkS2k1FkCaq2TcgNmtHB9w8=; b=E1RRct55iafbd8WNT8tGdJeHb2eGiXxLH7RQHQB0wYnWZd/RkcsekGyt9/N9aqD28O Adg/XL0KqWAGNGKpfmw4InmGp/kNDwIdfL8a71RDsAE+rRlY+qxOxeFXoVtS6OFerGQD qjcxDbzP6dFsj9e8dpHK2EOjRz13j+DIBTuVlF55wI9id1D2lccNAFUFW4AuDWZwAt/J 8HCvbbdIhjAy2z21VUQwBtGlqfde8eOMleEq39oEEoqQjiU8/ZVdcLu+PELkyTSSPzfx 3+cERGJaVkTzPLttt75NHjcL9QW4WMhUhKaeGKLdsXVYev8X3BwI8srXSUAFtX0I73xi 4WKQ== X-Gm-Message-State: AJIora8vksff/R1TuOTZQHn/04tmn/ZZnyvhQr2+hYbAjrQBIP51Laj1 4aFetGqtC5XpqqurxQ8iW5d6Qxh8Lsaq61TXN1s= X-Google-Smtp-Source: AGRyM1u39p8LsNLN5QDBQqApbbnXq6QehY4cZtGOoda3GVQm5WQIb47ThAB08yL1BKFo1IzMvE0TGABxt/gg8mQM5u0= X-Received: by 2002:a05:600c:3510:b0:3a3:34e7:cfc8 with SMTP id h16-20020a05600c351000b003a334e7cfc8mr6773219wmq.164.1658511382374; Fri, 22 Jul 2022 10:36:22 -0700 (PDT) MIME-Version: 1.0 References: <20220721152314.RFC.1.Ie333b3e4aff6e4a5b58c4aa805e030e561be8773@changeid> <269f2610-425b-f296-dcfc-89bdc2e1d587@quicinc.com> In-Reply-To: From: Rob Clark Date: Fri, 22 Jul 2022 10:36:44 -0700 Message-ID: Subject: Re: [RFC PATCH] drm/edid: Make 144 Hz not preferred on Sharp LQ140M1JW46 To: Doug Anderson Content-Type: text/plain; charset="UTF-8" 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: Sankeerth Billakanti , Thomas Zimmermann , David Airlie , Abhinav Kumar , dri-devel , LKML , freedreno Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, Jul 22, 2022 at 9:48 AM Doug Anderson wrote: > > Hi, > > On Fri, Jul 22, 2022 at 9:37 AM Abhinav Kumar wrote: > > > > + sankeerth > > > > Hi Doug > > > > On 7/21/2022 3:23 PM, Douglas Anderson wrote: > > > The Sharp LQ140M1JW46 panel is on the Qualcomm sc7280 CRD reference > > > board. This panel supports 144 Hz and 60 Hz. In the EDID, the 144 Hz > > > mode is listed first and thus is marked preferred. The EDID decode I > > > ran says: > > > > > > First detailed timing includes the native pixel format and preferred > > > refresh rate. > > > > > > ... > > > > > > Detailed Timing Descriptors: > > > DTD 1: 1920x1080 143.981 Hz 16:9 166.587 kHz 346.500 MHz > > > Hfront 48 Hsync 32 Hback 80 Hpol N > > > Vfront 3 Vsync 5 Vback 69 Vpol N > > > DTD 2: 1920x1080 59.990 Hz 16:9 69.409 kHz 144.370 MHz > > > Hfront 48 Hsync 32 Hback 80 Hpol N > > > Vfront 3 Vsync 5 Vback 69 Vpol N > > > > > > I'm proposing here that the above is actually a bug and that the 60 Hz > > > mode really should be considered preferred by Linux. > > > > > > The argument here is that this is a laptop panel and on a laptop we > > > know power will always be a concern. Presumably even if someone using > > > this panel wanted to use 144 Hz for some use cases they would only do > > > so dynamically and would still want the default to be 60 Hz. > > > > > > Let's change the default to 60 Hz using a standard quirk. > > > > > > Signed-off-by: Douglas Anderson > > > > Yes, we were aware that 144Hz was getting picked. We found that while > > debugging the screen corruption issue. > > > > Well, yes power would be less with 60Hz but so will be the performance. > > What performance specifically will be less with 60 Hz? In general the > sc7280 CPU is a bit memory-bandwidth constrained and the LCD refresh > from memory is a non-trivial part of that. Reducing to 60 Hz will > relieve some of the memory bandwidth pressure and will actually allow > tasks on the CPU to run _faster_. I guess the downside is that some > animations might be a little less smooth... I guess he is referring to something that is vblank sync'd running faster than 60fps. but OTOH it is a bit of a waste for fbcon to be using 144Hz. And there are enough android games that limit themselves to 30fps to save your "phone" battery. So it seems a lot more sane to default to 60Hz and let userspace that knows it wants more pick the 144Hz rate when needed. BR, -R > > > > The test teams have been validating with 144Hz so far so we are checking > > internally with the team whether its OKAY to goto 60Hz now since that > > kind of invalidates the testing they have been doing. > > You're worried that the panel itself won't work well at 60 Hz, or > something else about the system won't? The whole system in general > needs to work well with 60 Hz displays and I expect them to be much > more common than 144 Hz displays. Quite honestly if switching to 60 Hz > uncovers a problem that would be a huge benefit of landing this patch > because it would mean we'd find it now rather than down the road when > someone hooks up a different panel. > > -Doug