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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 BA0EDC433DF for ; Sat, 4 Jul 2020 14:52:19 +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 952192070C for ; Sat, 4 Jul 2020 14:52:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 952192070C 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 680976E0C5; Sat, 4 Jul 2020 14:52:18 +0000 (UTC) Received: from asavdk4.altibox.net (asavdk4.altibox.net [109.247.116.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id A52076E0C5 for ; Sat, 4 Jul 2020 14:52:16 +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 0FB1380512; Sat, 4 Jul 2020 16:52:14 +0200 (CEST) Date: Sat, 4 Jul 2020 16:52:12 +0200 From: Sam Ravnborg To: Mark Cave-Ayland Subject: Re: Panic booting qemu-system-sparc64 with bochs_drm Message-ID: <20200704145212.GA791554@ravnborg.org> References: <671ea432-7e2b-ab37-225e-fd32aef9a3e3@ilande.co.uk> <20200704072305.GA689588@ravnborg.org> <02fbd875-f6fd-da20-6835-778bdd6426c3@ilande.co.uk> <485ded46-c1a3-1eab-eb95-1a771543fbaf@ilande.co.uk> <20200704134115.GA755192@ravnborg.org> <1d19833f-2977-a12f-f3a9-ef0d509ef366@ilande.co.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1d19833f-2977-a12f-f3a9-ef0d509ef366@ilande.co.uk> 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=kj9zAlcOel0A:10 a=3GLR1-XzZKwA:10 a=e5mUnYsNAAAA:8 a=Nss-hjO5630hpDDf15kA:9 a=CjuIK1q_8ugA:10 a=Vxmtnl_E_bksehYqCbjh: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: Gerd Hoffmann , dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Mark. On Sat, Jul 04, 2020 at 03:16:47PM +0100, Mark Cave-Ayland wrote: > On 04/07/2020 14:41, Sam Ravnborg wrote: > > > I think what is happening is that the bochs driver request a shadow copy > > for the frambuffer. And with the change to fbops we now use the cfb_ > > functions to write to the shadow framebuffer - which is not in any IO > > space. So this does not work. > > > > So maybe all we need is the fix in drm_fb_helper_dirty_blit_real(). > > If you try to undo the change so fbops is set to &drm_fbdev_fb_ops, > > but keep the fix in drm_fb_helper_dirty_blit_real() how does it then > > behave? > > Bingo! I just tried that and the framebuffer is now working under qemu-system-sparc64 > again - thank you so much for the help! From what you said I guess > drm_fb_helper_dirty_blit_real() is responsible syncing the shadow copy? > > Below is the current working diff based upon your previous one: it certainly feels > like the difference in memcpy() behaviour should be hidden away in fb_memcpy_tofb() > or similar. >From your feedback so far I thnk the minimal fix would be like this: > --- a/drivers/gpu/drm/drm_fb_helper.c > +++ b/drivers/gpu/drm/drm_fb_helper.c > .. static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper *fb_helper, > size_t len = (clip->x2 - clip->x1) * cpp; > unsigned int y; > > for (y = clip->y1; y < clip->y2; y++) { > - memcpy(dst, src, len); > + fb_memcpy_tofb(dst, src, len); > src += fb->pitches[0]; > dst += fb->pitches[0]; > } (Hand edited, patch s not a valid syntax) But I need feedback from someone that know all this a bit better to judge if this is an OK change. For once - this will only work with shadow buffers. Sam > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index 6c3ef49b46b3..dce9adf7d189 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -865,6 +865,15 @@ struct drm_mode_config { > */ > bool prefer_shadow_fbdev; > > + /** > + * @use_cfb_for_fbdev: > + * > + * Use cfb variants of drm_fb_helper_cfb_{fillrect,copyarea,imageblit} > + * The cfb variants are required when the CPU do not allow direct > + * access to the framebuffer (for example sparc64) > + */ > + bool use_cfb_for_fbdev; > + > /** > * @quirk_addfb_prefer_xbgr_30bpp: > * > > > I did not find time to follow your instructions to test this myself with > > qemu - sorry. > > No worries, I do appreciate that as a maintainer it can be hard to fit these things > around life, family, job etc. > > > ATB, > > Mark. > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel