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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 36A22C433E1 for ; Fri, 3 Jul 2020 14:26:13 +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 171902088E for ; Fri, 3 Jul 2020 14:26:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 171902088E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ravnborg.org 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 6151F6E297; Fri, 3 Jul 2020 14:26:12 +0000 (UTC) Received: from asavdk4.altibox.net (asavdk4.altibox.net [109.247.116.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0D5CD6E297 for ; Fri, 3 Jul 2020 14:26:11 +0000 (UTC) Received: from ravnborg.org (unknown [188.228.123.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id C9D08804EB; Fri, 3 Jul 2020 16:26:08 +0200 (CEST) Date: Fri, 3 Jul 2020 16:26:07 +0200 From: Sam Ravnborg To: Paul Cercueil Subject: Re: [PATCH] drm/dbi: Fix SPI Type 1 (9-bit) transfer Message-ID: <20200703142607.GB25632@ravnborg.org> References: <20200703141341.1266263-1-paul@crapouillou.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200703141341.1266263-1-paul@crapouillou.net> X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=aP3eV41m c=1 sm=1 tr=0 a=S6zTFyMACwkrwXSdXUNehg==:117 a=S6zTFyMACwkrwXSdXUNehg==:17 a=8nJEP1OIZ-IA:10 a=VwQbUJbxAAAA:8 a=SJz97ENfAAAA:8 a=Ikd4Dj_1AAAA:8 a=QyXUC8HyAAAA:8 a=7gkXJVJtAAAA:8 a=WZHNqt2aAAAA:8 a=20KFwNOVAAAA:8 a=-VAfIpHNAAAA:8 a=e5mUnYsNAAAA:8 a=ER_8r6IbAAAA:8 a=UplYCoFZqbpoQR9uMNUA:9 a=wPNLvfGTeEIA:10 a=AjGcO6oz07-iQ99wixmX:22 a=vFet0B0WnEQeilDPIY6i:22 a=E9Po1WZjFZOl8hwRPBS3:22 a=PrHl9onO2p7xFKlKy1af:22 a=srlwD-8ojaedGGhPAyx8:22 a=Vxmtnl_E_bksehYqCbjh:22 a=9LHmKk7ezEChjTCyhBa9:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 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: Thomas Zimmermann , David Airlie , dri-devel@lists.freedesktop.org, stable@vger.kernel.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, Jul 03, 2020 at 04:13:41PM +0200, Paul Cercueil wrote: > The function mipi_dbi_spi1_transfer() will transfer its payload as 9-bit > data, the 9th (MSB) bit being the data/command bit. In order to do that, > it unpacks the 8-bit values into 16-bit values, then sets the 9th bit if > the byte corresponds to data, clears it otherwise. The 7 MSB are > padding. The array of now 16-bit values is then passed to the SPI core > for transfer. > = > This function was broken since its introduction, as the length of the > SPI transfer was set to the payload size before its conversion, but the > payload doubled in size due to the 8-bit -> 16-bit conversion. > = > Fixes: 02dd95fe3169 ("drm/tinydrm: Add MIPI DBI support") > Cc: # 4.10 "dim fixes 02dd95fe3169" provides the following output: Fixes: 02dd95fe3169 ("drm/tinydrm: Add MIPI DBI support") Cc: Noralf Tr=F8nnes Cc: Thierry Reding Cc: David Airlie Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: "Noralf Tr=F8nnes" Cc: Sam Ravnborg Cc: David Lechner Cc: Hans de Goede Cc: Eric Anholt Cc: dri-devel@lists.freedesktop.org Cc: # v4.11+ I assume the "Cc: # 4.11+" is more correct? Sam > Signed-off-by: Paul Cercueil > --- > drivers/gpu/drm/drm_mipi_dbi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > = > diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_db= i.c > index bb27c82757f1..bf7888ad9ad4 100644 > --- a/drivers/gpu/drm/drm_mipi_dbi.c > +++ b/drivers/gpu/drm/drm_mipi_dbi.c > @@ -923,7 +923,7 @@ static int mipi_dbi_spi1_transfer(struct mipi_dbi *db= i, int dc, > } > } > = > - tr.len =3D chunk; > + tr.len =3D chunk * 2; > len -=3D chunk; > = > ret =3D spi_sync(spi, &m); > -- = > 2.27.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel