From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 02 Jun 2026 17:20:57 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wUQvJ-001cew-16 for lore@lore.pengutronix.de; Tue, 02 Jun 2026 17:20:57 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1wUQvI-0003iC-KG for lore@pengutronix.de; Tue, 02 Jun 2026 17:20:57 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=9HSYrVifcwAxOop4+b3pkCUiaT76Pgb4d5aJ+Napczo=; b=g4J92BC35sSBVr4+gwrNqlrGV6 CM6rSrrgb96kCKWX3kv1QH6MJf4fYiFwweazHJpX6+jd+X6qvQpNI/snI6awKi3BTbpu2gc0OPhxX JwSLEQosUfypLv3uFn+cQEW8cLtRYuJLex0CbaHgqjZ00Odd/rTnTAGoHf4wthEA1ZUwL3zEtly5N sMp90gQMoCon3q2Ih9OxOvtIINUGBxqR/pcNaOB4UfA4GHHg6hC5LTldYNpeVQgmzUbLbRDTEuI9z RndqUVjnpEnbTc2YeHD/ex63b5Fq27PKyQaqj87VADp7WYniIVVFdi4bccbYnQ/KTb65Z27ELk/1h 8X/AGPJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wUQsL-0000000DJQW-3dqN; Tue, 02 Jun 2026 15:17:53 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wUQsD-0000000DJD6-2q2j for barebox@lists.infradead.org; Tue, 02 Jun 2026 15:17:49 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id EDC7F43838; Tue, 2 Jun 2026 15:17:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C4FC1F00898; Tue, 2 Jun 2026 15:17:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780413464; bh=9HSYrVifcwAxOop4+b3pkCUiaT76Pgb4d5aJ+Napczo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=TVABfYLfLf6/obK083C0whlJzVpQFDRY/phNATDQxW0l7xsd/np4Jf6jMSmDMwAq4 KkvOKf8tk/k1rRelJWkBey3J4pY/IaxhdtcYpZibWAbj2atRwmuRualBqJsP3os6bD SY+ZOL6rq0BM8DMLz4nQrB8E7EIEMBCMDHuY+mR0xvg6ghZzenGxrQl46mtzVjJrZU gWO8YzyyMkeTSrQtXiVaSfGEJ0/wplzU/Edcsz1TLdGbf99DYS+zhvJXdFvD+IxFWC axkJLlgS9A4J+FFkBiSzmFnnR3ynpnXU9j22Yu1JDAGTv2dDcY4JWnNrJXZol16XrT xxzZKpDeG4B+g== Date: Tue, 2 Jun 2026 17:17:40 +0200 From: Michael Grzeschik To: Lucas Stach Cc: Ahmad Fatoum , Johannes Schneider , barebox@lists.infradead.org, thomas.haemmerle@leica-geosystems.com Message-ID: References: <20260602040953.1060278-1-johannes.schneider@leica-geosystems.com> <20260602040953.1060278-7-johannes.schneider@leica-geosystems.com> <54467182b9e4f15a1ac068533e73aaac5f21bf46.camel@pengutronix.de> <679f1823-5edd-4a8f-8a8e-caf6db7dd483@pengutronix.de> <9bf1b5920ca2c986533c5f17d10aa774aa60c895.camel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <9bf1b5920ca2c986533c5f17d10aa774aa60c895.camel@pengutronix.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260602_081745_986127_C3F2EB93 X-CRM114-Status: GOOD ( 38.16 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-105.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, USER_IN_WELCOMELIST,USER_IN_WHITELIST autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 6/6] video: imx-lcdif: drain write-combine buffer before LCDIF DMA reads pixels X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hi Johannes On Tue, Jun 02, 2026 at 02:12:43PM +0200, Lucas Stach wrote: > Am Dienstag, dem 02.06.2026 um 11:37 +0200 schrieb Ahmad Fatoum: > > > > On 6/2/26 10:12 AM, Lucas Stach wrote: > > > Am Dienstag, dem 02.06.2026 um 04:09 +0000 schrieb Johannes Schneider: > > > > From: Thomas Haemmerle > > > > > > > > The LCDIF framebuffer is allocated as Normal Non-Cacheable (write-combine) > > > > memory. After the splash command calls gu_screen_blit(), which copies the > > > > decoded PNG via memcpy() from a cached shadow buffer into the hardware > > > > framebuffer, writes may still reside in the CPU write buffer and not yet > > > > be visible to the LCDIF DMA engine. On hardware this manifests as > > > > partial or corrupted rendering — the bottom portion of the splash image > > > > renders black or shows garbage. > > > > > > > > Implement fb_damage() to execute a DSB SY barrier after each blit, > > > > ensuring all pending write-combine writes are committed to DRAM before > > > > the LCDIF reads the pixel data. > > > > > > > > Assisted-by: Claude:claude-sonnet-4-6 > > > > Signed-of-by: Thomas Haemmerle > > > > --- > > > > drivers/video/imx-lcdif.c | 13 +++++++++++++ > > > > 1 file changed, 13 insertions(+) > > > > > > > > diff --git a/drivers/video/imx-lcdif.c b/drivers/video/imx-lcdif.c > > > > index ae5976c771..8d9b40be0f 100644 > > > > --- a/drivers/video/imx-lcdif.c > > > > +++ b/drivers/video/imx-lcdif.c > > > > @@ -20,6 +20,7 @@ > > > > #include > > > > #include