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 0495BCCA473 for ; Sun, 3 Jul 2022 11:45:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232373AbiGCLpc (ORCPT ); Sun, 3 Jul 2022 07:45:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229993AbiGCLpb (ORCPT ); Sun, 3 Jul 2022 07:45:31 -0400 Received: from aposti.net (aposti.net [89.234.176.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 765C963BB; Sun, 3 Jul 2022 04:45:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1656848728; h=from:from:sender: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=sXnapAA8AB7IePhGfDT35N7Hgo2H+tcnMEbnApSgbgc=; b=NrlNvnLQqaM9/3j5GyuFg5OW9YqnMc4LaDWtfmSJ+w/+y4rwR/bRs6CscjrRLvprIugR9f HTqN3nj4q/n/eDV5pTR8WQFolR6qQoFSwPuqgGWaLIwrX30n3SJyLgtumddYNmCkxDvSS+ M3ZLmGd665inHTDo0y5E+dfT9rbwBgY= Date: Sun, 03 Jul 2022 12:45:18 +0100 From: Paul Cercueil Subject: Re: [PATCH] drm/ingenic: Use the highest possible DMA burst size To: Sam Ravnborg Cc: David Airlie , Daniel Vetter , linux-mips@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, list@opendingux.net, Christophe Branchereau , stable@vger.kernel.org Message-Id: In-Reply-To: References: <20220702230727.66704-1-paul@crapouillou.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Sam, Le dim., juil. 3 2022 at 08:43:37 +0200, Sam Ravnborg=20 a =E9crit : > Hi Paul, >=20 > On Sun, Jul 03, 2022 at 12:07:27AM +0100, Paul Cercueil wrote: >> Until now, when running at the maximum resolution of 1280x720 at=20 >> 32bpp >> on the JZ4770 SoC the output was garbled, the X/Y position of the >> top-left corner of the framebuffer warping to a random position with >> the whole image being offset accordingly, every time a new frame was >> being submitted. >>=20 >> This problem can be eliminated by using a bigger burst size for the=20 >> DMA. >=20 > Are there any alignment constraints of the framebuffer that depends on > the burst size? I am hit by this with some atmel IP - which is why I > ask. I would think that the framebuffer needs to be aligned with the burst=20 size, indeed. Here, our buffers are always page-aligned so that's not a=20 problem. > Patch looks good and is a-b. Thanks! Cheers, -Paul >>=20 >> Set in each soc_info structure the maximum burst size supported by=20 >> the >> corresponding SoC, and use it in the driver. >>=20 >> Set the new value using regmap_update_bits() instead of >> regmap_set_bits(), since we do want to override the old value of the >> burst size. (Note that regmap_set_bits() wasn't really valid before=20 >> for >> the same reason, but it never seemed to be a problem). >>=20 >> Cc: >> Fixes: 90b86fcc47b4 ("DRM: Add KMS driver for the Ingenic JZ47xx=20 >> SoCs") >> Signed-off-by: Paul Cercueil > Acked-by: Sam Ravnborg