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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 1E9A1C433E2 for ; Tue, 8 Sep 2020 19:43:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 970292166E for ; Tue, 8 Sep 2020 19:43:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=agner.ch header.i=@agner.ch header.b="GY7avC89" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732387AbgIHTnT (ORCPT ); Tue, 8 Sep 2020 15:43:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730866AbgIHPwh (ORCPT ); Tue, 8 Sep 2020 11:52:37 -0400 Received: from mail.kmu-office.ch (mail.kmu-office.ch [IPv6:2a02:418:6a02::a2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE3B3C06179F for ; Tue, 8 Sep 2020 05:07:32 -0700 (PDT) Received: from webmail.kmu-office.ch (unknown [IPv6:2a02:418:6a02::a3]) by mail.kmu-office.ch (Postfix) with ESMTPSA id B45EE5C4CAB; Tue, 8 Sep 2020 14:07:19 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1599566839; h=from:from: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=9/iGAOA8cGPooGWY1bJsYTg01+jVFtO35sVIw145pes=; b=GY7avC89iAWwVC2ntJkGy9B4XIrrInU5rnAqJX2IcIa1H0DBshBq+BWnQ0X3DHK1EY1el9 HZXQHNp4dzu2FT5vC3yksXHKYfQEFJaNR2CxVZo0cPVJdkMUQblLdbVDXKWiN64VtIsnjG M05Ummpf4PiVLVIVBqstvK1YLaDAtiM= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Tue, 08 Sep 2020 14:07:19 +0200 From: Stefan Agner To: Tomi Valkeinen Cc: Laurent Pinchart , jsarha@ti.com, marex@denx.de, airlied@linux.ie, daniel@ffwll.ch, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm: mxsfb: check framebuffer pitch In-Reply-To: <20200908084855.GH2352366@phenom.ffwll.local> References: <20200907160343.124405-1-stefan@agner.ch> <20200907161712.GF6047@pendragon.ideasonboard.com> <20200907181855.GE2352366@phenom.ffwll.local> <86615b4b1551d4a6f1cfcc13b38e616c@agner.ch> <20200908084855.GH2352366@phenom.ffwll.local> User-Agent: Roundcube Webmail/1.4.1 Message-ID: X-Sender: stefan@agner.ch Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-09-08 10:48, Daniel Vetter wrote: > On Tue, Sep 08, 2020 at 11:18:25AM +0300, Tomi Valkeinen wrote: >> Hi, >> >> On 08/09/2020 10:55, Stefan Agner wrote: >> > On 2020-09-07 20:18, Daniel Vetter wrote: >> >> On Mon, Sep 07, 2020 at 07:17:12PM +0300, Laurent Pinchart wrote: >> >>> Hi Stefan, >> >>> >> >>> Thank you for the patch. >> >>> >> >>> On Mon, Sep 07, 2020 at 06:03:43PM +0200, Stefan Agner wrote: >> >>>> The lcdif IP does not support a framebuffer pitch (stride) other than >> >>>> the CRTC width. Check for equality and reject the state otherwise. >> >>>> >> >>>> This prevents a distorted picture when using 640x800 and running the >> >>>> Mesa graphics stack. Mesa tires to use a cache aligned stride, which >> >>> >> >>> s/tires/tries/ >> >>> >> >>>> leads at that particular resolution to width != stride. Currently >> >>>> Mesa has no fallback behavior, but rejecting this configuration allows >> >>>> userspace to handle the issue correctly. >> >>> >> >>> I'm increasingly impressed by how featureful this IP core is :-) >> >>> >> >>>> Signed-off-by: Stefan Agner >> >>>> --- >> >>>> drivers/gpu/drm/mxsfb/mxsfb_kms.c | 22 ++++++++++++++++++---- >> >>>> 1 file changed, 18 insertions(+), 4 deletions(-) >> >>>> >> >>>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c >> >>>> index b721b8b262ce..79aa14027f91 100644 >> >>>> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c >> >>>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c >> >>>> @@ -403,14 +403,28 @@ static int mxsfb_plane_atomic_check(struct drm_plane *plane, >> >>>> { >> >>>> struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev); >> >>>> struct drm_crtc_state *crtc_state; >> >>>> + unsigned int pitch; >> >>>> + int ret; >> >>>> >> >>>> crtc_state = drm_atomic_get_new_crtc_state(plane_state->state, >> >>>> &mxsfb->crtc); >> >>>> >> >>>> - return drm_atomic_helper_check_plane_state(plane_state, crtc_state, >> >>>> - DRM_PLANE_HELPER_NO_SCALING, >> >>>> - DRM_PLANE_HELPER_NO_SCALING, >> >>>> - false, true); >> >>>> + ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state, >> >>>> + DRM_PLANE_HELPER_NO_SCALING, >> >>>> + DRM_PLANE_HELPER_NO_SCALING, >> >>>> + false, true); >> >>>> + if (ret || !plane_state->visible) >> >>> >> >>> Would it be more explict to check for !plane_state->fb ? Otherwise I'll >> >>> have to verify that !fb always implies !visible :-) >> >>> >> >>>> + return ret; >> >>>> + >> >>>> + pitch = crtc_state->mode.hdisplay * >> >>>> + plane_state->fb->format->cpp[0]; >> >>> >> >>> This holds on a single line. >> >>> >> >>>> + if (plane_state->fb->pitches[0] != pitch) { >> >>>> + dev_err(plane->dev->dev, >> >>>> + "Invalid pitch: fb and crtc widths must be the same"); >> >>> >> >>> I'd turn this into a dev_dbg(), printing error messages to the kernel >> >>> log in response to user-triggered conditions is a bit too verbose and >> >>> could flood the log. >> >>> >> >>> Wouldn't it be best to catch this issue when creating the framebuffer ? >> >> >> >> Yeah this should be verified at addfb time. We try to validate as early as >> >> possible. >> >> -Daniel >> >> >> > >> > Sounds sensible. From what I can tell fb_create is the proper callback >> > to implement this at addfb time. Will give this a try. >> > >> > FWIW, I got the idea from drivers/gpu/drm/tilcdc/tilcdc_plane.c. Maybe >> > should be moved to addfb there too? >> >> But you don't know the crtc width when creating the framebuffer. > > Hm right this is a different check. What we could check in fb_create for > both is that the logical fb size matches exactly the pitch. That's not > sufficient criteria, but it will at least catch some of them already. > > But yeah we'd need both here. After validating width of framebuffer against pitch, the only thing we need to check here is that the width matches. From what I can tell, least for mxsfb, this should be covered by drm_atomic_helper_check_plane_state's can_position parameter set to false. So I think in my case I can get away by only checking the framebuffer. -- Stefan > -Daniel > >> >> Tomi >> >> -- >> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. >> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki