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=-13.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 4E462C43387 for ; Mon, 7 Jan 2019 10:08:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05E7920854 for ; Mon, 7 Jan 2019 10:08:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="JwKl19Wg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726540AbfAGKIs (ORCPT ); Mon, 7 Jan 2019 05:08:48 -0500 Received: from mail-ed1-f65.google.com ([209.85.208.65]:34475 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726654AbfAGKIs (ORCPT ); Mon, 7 Jan 2019 05:08:48 -0500 Received: by mail-ed1-f65.google.com with SMTP id b3so329305ede.1 for ; Mon, 07 Jan 2019 02:08:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=sender:date:from:to:cc:subject:message-id:mail-followup-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=RDnt6qLaS59xIovYIhHYFf5cjY9EzLWq8SNUgTs+I9g=; b=JwKl19Wgb38EI75Ec3DBXJSwWDU+z7lmFrG/qP8DIZ4LumRna4M7aE5D1qOJlQpG4e VYIqECc1pZs1swKMhk6LODKuvBncxzwcEmACtyQK//EgnnrPKduw2wvuSAme41lbPtTm jU2hYWhdFCayxLL0sthdavc3G/hmKMlrA7Xl8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to:user-agent; bh=RDnt6qLaS59xIovYIhHYFf5cjY9EzLWq8SNUgTs+I9g=; b=TMe65fVegg09Q8MLEarWhCsLdVNUbBnR83Fq491IpKA6ZYk39kvjwpM4yL7gpy80u7 m6zWm3G+sZ5jkPMpY8h5VwFQW6f4OM0vHhRnI9xfQwUp/MpU9qlyY29dFpU1OavkpPie +RDBeVrLt9P0voKZ065kI0bLKvBexC7uO5L+n6xwQ/JOnU7NHLjYUgSFGSWlRtLJcQf/ BBXW2WjGhR2pmUNdnAGYvZ6sgIc6xn1ahyksj0P+i4Hvlows1TaxhKWeAZCXB9O/FyfU ZW3uzWjm7j72CFs4axW09b0t2bp68TUQ1sxLscX9v1xu6iBoei6MRY1lC0IfOmFqveZM fQdA== X-Gm-Message-State: AJcUuke6Oi4tY3tekynh5IBR2yOAaGws52Xx/XDvb+Xel9c22gW9LW+K 3T7s2EcxbEKgllmvDDiaCCXspA== X-Google-Smtp-Source: ALg8bN4mfE0GESZWFR+w0oW7lDQiFRMHeGsiOVGH2xH+XtL/XckNpKt0eNce0UKV9YwjgnJOPJacOw== X-Received: by 2002:a17:906:f108:: with SMTP id gv8-v6mr29428457ejb.173.1546855725514; Mon, 07 Jan 2019 02:08:45 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id d56sm30981734ede.76.2019.01.07.02.08.44 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 07 Jan 2019 02:08:44 -0800 (PST) Date: Mon, 7 Jan 2019 11:08:42 +0100 From: Daniel Vetter To: Ivan Mironov Cc: Daniel Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , saahriktu , Eugeniy Paltsev , stable@vger.kernel.org Subject: Re: [PATCH v1 1/2] drm/fb-helper: Bring back workaround for bugs of SDL 1.2 Message-ID: <20190107100842.GZ21184@phenom.ffwll.local> Mail-Followup-To: Ivan Mironov , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , saahriktu , Eugeniy Paltsev , stable@vger.kernel.org References: <20181227231308.16904-1-mironov.ivan@gmail.com> <20181227231308.16904-2-mironov.ivan@gmail.com> <20181228121549.GU9058@dvetter-linux.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 4.18.0-2-amd64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sat, Jan 05, 2019 at 09:11:53PM +0500, Ivan Mironov wrote: > On Fri, 2018-12-28 at 13:15 +0100, Daniel Vetter wrote: > > On Fri, Dec 28, 2018 at 04:13:07AM +0500, Ivan Mironov wrote: > > > SDL 1.2 sets all fields related to the pixel format to zero in some > > > cases[1]. Prior to commit db05c48197759 ("drm: fb-helper: Reject all > > > pixel format changing requests"), there was an unintentional workaround > > > for this that existed for more than a decade. First in device-specific DRM > > > drivers, then here in drm_fb_helper.c. > > > > > > Previous code containing this workaround just ignores pixel format fields > > > from userspace code. Not a good thing either, as this way, driver may > > > silently use pixel format different from what client actually requested, > > > and this in turn will lead to displaying garbage on the screen. I think > > > that returning EINVAL to userspace in this particular case is the right > > > option, so I decided to left code from problematic commit untouched > > > instead of just reverting it entirely. > > > > > > Here is the steps required to reproduce this problem exactly: > > > 1) Compile fceux[2] with SDL 1.2.15 and without GTK or OpenGL > > > support. SDL should be compiled with fbdev support (which is > > > on by default). > > > 2) Create /etc/fb.modes with following contents (values seems > > > not used, and just required to trigger problematic code in > > > SDL): > > > > > > mode "test" > > > geometry 1 1 1 1 1 > > > timings 1 1 1 1 1 1 1 > > > endmode > > > > > > 3) Create ~/.fceux/fceux.cfg with following contents: > > > > > > SDL.Hotkeys.Quit = 27 > > > SDL.DoubleBuffering = 1 > > > > > > 4) Ensure that screen resolution is at least 1280x960 (e.g. > > > append "video=Virtual-1:1280x960-32" to the kernel cmdline > > > for qemu/QXL). > > > > > > 5) Try to run fceux on VT with some ROM file[3]: > > > > > > # ./fceux color_test.nes > > > > > > [1] SDL 1.2.15 source code, src/video/fbcon/SDL_fbvideo.c, > > > FB_SetVideoMode() > > > [2] http://www.fceux.com > > > [3] Example ROM: https://github.com/bokuweb/rustynes/blob/master/roms/color_test.nes > > > > > > Reported-by: saahriktu > > > Suggested-by: saahriktu > > > Cc: stable@vger.kernel.org > > > Fixes: db05c48197759 ("drm: fb-helper: Reject all pixel format changing requests") > > > Signed-off-by: Ivan Mironov > > > --- > > > drivers/gpu/drm/drm_fb_helper.c | 146 ++++++++++++++++++++------------ > > > 1 file changed, 93 insertions(+), 53 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c > > > index d3af098b0922..aff576c3c4fb 100644 > > > --- a/drivers/gpu/drm/drm_fb_helper.c > > > +++ b/drivers/gpu/drm/drm_fb_helper.c > > > @@ -1621,6 +1621,64 @@ static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1, > > > var_1->transp.msb_right == var_2->transp.msb_right; > > > } > > > > > > +static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var, > > > + u8 depth) > > > +{ > > > + switch (depth) { > > > + case 8: > > > + var->red.offset = 0; > > > + var->green.offset = 0; > > > + var->blue.offset = 0; > > > + var->red.length = 8; /* 8bit DAC */ > > > + var->green.length = 8; > > > + var->blue.length = 8; > > > + var->transp.offset = 0; > > > + var->transp.length = 0; > > > + break; > > > + case 15: > > > + var->red.offset = 10; > > > + var->green.offset = 5; > > > + var->blue.offset = 0; > > > + var->red.length = 5; > > > + var->green.length = 5; > > > + var->blue.length = 5; > > > + var->transp.offset = 15; > > > + var->transp.length = 1; > > > + break; > > > + case 16: > > > + var->red.offset = 11; > > > + var->green.offset = 5; > > > + var->blue.offset = 0; > > > + var->red.length = 5; > > > + var->green.length = 6; > > > + var->blue.length = 5; > > > + var->transp.offset = 0; > > > + break; > > > + case 24: > > > + var->red.offset = 16; > > > + var->green.offset = 8; > > > + var->blue.offset = 0; > > > + var->red.length = 8; > > > + var->green.length = 8; > > > + var->blue.length = 8; > > > + var->transp.offset = 0; > > > + var->transp.length = 0; > > > + break; > > > + case 32: > > > + var->red.offset = 16; > > > + var->green.offset = 8; > > > + var->blue.offset = 0; > > > + var->red.length = 8; > > > + var->green.length = 8; > > > + var->blue.length = 8; > > > + var->transp.offset = 24; > > > + var->transp.length = 8; > > > + break; > > > + default: > > > + break; > > > + } > > > +} > > > + > > > /** > > > * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var > > > * @var: screeninfo to check > > > @@ -1654,6 +1712,40 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var, > > > return -EINVAL; > > > } > > > > > > + /* > > > + * Workaround for SDL 1.2, which is known to be setting all pixel format > > > + * fields values to zero in some cases. We treat this situation as a > > > + * kind of "use some reasonable autodetected values". > > > + */ > > > + if (!var->red.offset && !var->green.offset && > > > + !var->blue.offset && !var->transp.offset && > > > + !var->red.length && !var->green.length && > > > + !var->blue.length && !var->transp.length && > > > + !var->red.msb_right && !var->green.msb_right && > > > + !var->blue.msb_right && !var->transp.msb_right) { > > > + u8 depth; > > > + > > > + /* > > > + * There is no way to guess the right value for depth when > > > + * bpp is 16 or 32. So we just restore the behaviour previously > > > + * introduced here by commit . In fact, this was > > > + * implemented even earlier in various device drivers. > > > + */ > > > + switch (var->bits_per_pixel) { > > > + case 16: > > > + depth = 15; > > > + break; > > > + case 32: > > > + depth = 24; > > > + break; > > > + default: > > > + depth = var->bits_per_pixel; > > > + break; > > > + } > > > + > > > + drm_fb_helper_fill_pixel_fmt(var, depth); > > > > Please use fb->format->depth here instead of guessing. > > -Daniel > > I do not think that this is the right way. > > Without guessing, if SDL1 makes a request with bits_per_pixel == 16 > (for example) and current fb->format->depth == 24, ioctl() will succeed > while actual pixel format will remain the same. As a result, SDL1 will > display garbage because of invalid pixel format. > > Or am I missing something here? This is supposed to be the case where SDL didn't set any of this stuff. Guess is definitely not what we want to do, we should use the actual depth, which is stored in fb->format->depth. Older code did guess, but we fixed that, and shouldn't reintroduce that guess game. -Daniel > > > > + } > > > + > > > /* > > > * drm fbdev emulation doesn't support changing the pixel format at all, > > > * so reject all pixel format changing requests.oid drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe info->var.yoffset = 0; info->var.activate = FB_ACTIVATE_NOW; > > > - switch (fb->format->depth) { > > > - case 8: > > > - info->var.red.offset = 0; > > > - info->var.green.offset = 0; > > > - info->var.blue.offset = 0; > > > - info->var.red.length = 8; /* 8bit DAC */ > > > - info->var.green.length = 8; > > > - info->var.blue.length = 8; > > > - info->var.transp.offset = 0; > > > - info->var.transp.length = 0; > > > - break; > > > - case 15: > > > - info->var.red.offset = 10; > > > - info->var.green.offset = 5; > > > - info->var.blue.offset = 0; > > > - info->var.red.length = 5; > > > - info->var.green.length = 5; > > > - info->var.blue.length = 5; > > > - info->var.transp.offset = 15; > > > - info->var.transp.length = 1; > > > - break; > > > - case 16: > > > - info->var.red.offset = 11; > > > - info->var.green.offset = 5; > > > - info->var.blue.offset = 0; > > > - info->var.red.length = 5; > > > - info->var.green.length = 6; > > > - info->var.blue.length = 5; > > > - info->var.transp.offset = 0; > > > - break; > > > - case 24: > > > - info->var.red.offset = 16; > > > - info->var.green.offset = 8; > > > - info->var.blue.offset = 0; > > > - info->var.red.length = 8; > > > - info->var.green.length = 8; > > > - info->var.blue.length = 8; > > > - info->var.transp.offset = 0; > > > - info->var.transp.length = 0; > > > - break; > > > - case 32: > > > - info->var.red.offset = 16; > > > - info->var.green.offset = 8; > > > - info->var.blue.offset = 0; > > > - info->var.red.length = 8; > > > - info->var.green.length = 8; > > > - info->var.blue.length = 8; > > > - info->var.transp.offset = 24; > > > - info->var.transp.length = 8; > > > - break; > > > - default: > > > - break; > > > - } > > > + drm_fb_helper_fill_pixel_fmt(&info->var, fb->format->depth); > > > > > > info->var.xres = fb_width; > > > info->var.yres = fb_height; > > > -- > > > 2.20.1 > > > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch