From patchwork Tue Jan 25 09:12:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 12723521 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4130C433F5 for ; Tue, 25 Jan 2022 09:18:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1457966AbiAYJRb (ORCPT ); Tue, 25 Jan 2022 04:17:31 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:44798 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1456724AbiAYJMl (ORCPT ); Tue, 25 Jan 2022 04:12:41 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 644412113B; Tue, 25 Jan 2022 09:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1643101945; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mmoavMi/ljQQ4OgjarT4CceYyJul5NBm4EuJtWQTphY=; b=nRDn6aPsnQZGLjhFoi6k19QZQ1r1s+HE8uMOQfCLUG+VPzgV6F5wonLEWJgy+9iS2NZlyf 8FL4q/IG8C1xBlQAzZP8fI1zG9XyDXUFpKPKBrtltlrr0SLSvOj6Ccro134WU2LWDkGSJj v7ZkQ9wjULPWLrmHNvLwZi0VpVz9ArQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1643101945; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mmoavMi/ljQQ4OgjarT4CceYyJul5NBm4EuJtWQTphY=; b=cl3rGfnG81BtBNfcKoRtoiXU2aM1S5kFkg19noogGPXi2oMqDUQ9khjRcJ2hKnin7swWXH 82XBP80w1vTCXqDA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 1A22A13DA3; Tue, 25 Jan 2022 09:12:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 4M5uBfm+72GGQAAAMHmgww (envelope-from ); Tue, 25 Jan 2022 09:12:25 +0000 From: Thomas Zimmermann To: zackr@vmware.com, javierm@redhat.com, jfalempe@redhat.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@linux.ie, daniel@ffwll.ch, deller@gmx.de, hdegoede@redhat.com Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Thomas Zimmermann , stable@vger.kernel.org Subject: [PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal Date: Tue, 25 Jan 2022 10:12:18 +0100 Message-Id: <20220125091222.21457-2-tzimmermann@suse.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220125091222.21457-1-tzimmermann@suse.de> References: <20220125091222.21457-1-tzimmermann@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hot-unplug all firmware-framebuffer devices as part of removing them via remove_conflicting_framebuffers() et al. Releases all memory regions to be acquired by native drivers. Firmware, such as EFI, install a framebuffer while posting the computer. After removing the firmware-framebuffer device from fbdev, a native driver takes over the hardware and the firmware framebuffer becomes invalid. Firmware-framebuffer drivers, specifically simplefb, don't release their device from Linux' device hierarchy. It still owns the firmware framebuffer and blocks the native drivers from loading. This has been observed in the vmwgfx driver. [1] Initiating a device removal (i.e., hot unplug) as part of remove_conflicting_framebuffers() removes the underlying device and returns the memory range to the system. [1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/ v2: * rename variable 'dev' to 'device' (Javier) Signed-off-by: Thomas Zimmermann Reported-by: Zack Rusin Reviewed-by: Javier Martinez Canillas Reviewed-by: Zack Rusin CC: stable@vger.kernel.org # v5.11+ --- drivers/video/fbdev/core/fbmem.c | 29 ++++++++++++++++++++++++++--- include/linux/fb.h | 1 + 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0fa7ede94fa6..b585339509b0 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -1557,18 +1558,36 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, /* check all firmware fbs and kick off if the base addr overlaps */ for_each_registered_fb(i) { struct apertures_struct *gen_aper; + struct device *device; if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE)) continue; gen_aper = registered_fb[i]->apertures; + device = registered_fb[i]->device; if (fb_do_apertures_overlap(gen_aper, a) || (primary && gen_aper && gen_aper->count && gen_aper->ranges[0].base == VGA_FB_PHYS)) { printk(KERN_INFO "fb%d: switching to %s from %s\n", i, name, registered_fb[i]->fix.id); - do_unregister_framebuffer(registered_fb[i]); + + /* + * If we kick-out a firmware driver, we also want to remove + * the underlying platform device, such as simple-framebuffer, + * VESA, EFI, etc. A native driver will then be able to + * allocate the memory range. + * + * If it's not a platform device, at least print a warning. A + * fix would add code to remove the device from the system. + */ + if (dev_is_platform(device)) { + registered_fb[i]->forced_out = true; + platform_device_unregister(to_platform_device(device)); + } else { + pr_warn("fb%d: cannot remove device\n", i); + do_unregister_framebuffer(registered_fb[i]); + } } } } @@ -1898,9 +1917,13 @@ EXPORT_SYMBOL(register_framebuffer); void unregister_framebuffer(struct fb_info *fb_info) { - mutex_lock(®istration_lock); + bool forced_out = fb_info->forced_out; + + if (!forced_out) + mutex_lock(®istration_lock); do_unregister_framebuffer(fb_info); - mutex_unlock(®istration_lock); + if (!forced_out) + mutex_unlock(®istration_lock); } EXPORT_SYMBOL(unregister_framebuffer); diff --git a/include/linux/fb.h b/include/linux/fb.h index 3da95842b207..9a14f3f8a329 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -502,6 +502,7 @@ struct fb_info { } *apertures; bool skip_vt_switch; /* no VT switch on suspend/resume required */ + bool forced_out; /* set when being removed by another driver */ }; static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {