linux/drivers/video/fbdev/core/fbcon.c, branch v5.8

drm/fb-helper: Fix vt restore

2020-06-24T19:34:11Z

In the past we had a pile of hacks to orchestrate access between fbdev emulation and native kms clients. We've tried to streamline this, by always preferring the kms side above fbdev calls when a drm master exists, because drm master controls access to the display resources. Unfortunately this breaks existing userspace, specifically Xorg. When exiting Xorg first restores the console to text mode using the KDSET ioctl on the vt. This does nothing, because a drm master is still around. Then it drops the drm master status, which again does nothing, because logind is keeping additional drm fd open to be able to orchestrate vt switches. In the past this is the point where fbdev was restored, as part of the ->lastclose hook on the drm side. Now to fix this regression we don't want to go back to letting fbdev restore things whenever it feels like, or to the pile of hacks we've had before. Instead try and go with a minimal exception to make the KDSET case work again, and nothing else. This means that if userspace does a KDSET call when switching between graphical compositors, there will be some flickering with fbcon showing up for a bit. But a) that's not a regression and b) userspace can fix it by improving the vt switching dance - logind should have all the information it needs. While pondering all this I'm also wondering wheter we should have a SWITCH_MASTER ioctl to allow race-free master status handover. But that's for another day. v2: Somehow forgot to cc all the fbdev people. v3: Fix typo Alex spotted. Reviewed-by: Alex Deucher Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=208179 Cc: shlomo@fastmail.com Reported-and-Tested-by: shlomo@fastmail.com Cc: Michel Dänzer Fixes: 64914da24ea9 ("drm/fbdev-helper: don't force restores") Cc: Noralf Trønnes Cc: Thomas Zimmermann Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Cc: # v5.7+ Cc: Bartlomiej Zolnierkiewicz Cc: Geert Uytterhoeven Cc: Nathan Chancellor Cc: Qiujun Huang Cc: Peter Rosin Cc: linux-fbdev@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200624092910.3280448-1-daniel.vetter@ffwll.ch

fbcon: fix null-ptr-deref in fbcon_switch

2020-03-31T07:59:38Z

Set logo_shown to FBCON_LOGO_CANSHOW when the vc was deallocated. syzkaller report: https://lkml.org/lkml/2020/3/27/403 general protection fault, probably for non-canonical address 0xdffffc000000006c: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367] RIP: 0010:fbcon_switch+0x28f/0x1740 drivers/video/fbdev/core/fbcon.c:2260 Call Trace: redraw_screen+0x2a8/0x770 drivers/tty/vt/vt.c:1008 vc_do_resize+0xfe7/0x1360 drivers/tty/vt/vt.c:1295 fbcon_init+0x1221/0x1ab0 drivers/video/fbdev/core/fbcon.c:1219 visual_init+0x305/0x5c0 drivers/tty/vt/vt.c:1062 do_bind_con_driver+0x536/0x890 drivers/tty/vt/vt.c:3542 do_take_over_console+0x453/0x5b0 drivers/tty/vt/vt.c:4122 do_fbcon_takeover+0x10b/0x210 drivers/video/fbdev/core/fbcon.c:588 fbcon_fb_registered+0x26b/0x340 drivers/video/fbdev/core/fbcon.c:3259 do_register_framebuffer drivers/video/fbdev/core/fbmem.c:1664 [inline] register_framebuffer+0x56e/0x980 drivers/video/fbdev/core/fbmem.c:1832 dlfb_usb_probe.cold+0x1743/0x1ba3 drivers/video/fbdev/udlfb.c:1735 usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:374 accessing vc_cons[logo_shown].d->vc_top causes the bug. Reported-by: syzbot+732528bae351682f1f27@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang Acked-by: Sam Ravnborg Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200329085647.25133-1-hqjagain@gmail.com

fbcon: Adjust indentation in set_con2fb_map

2020-01-15T16:31:46Z

Clang warns: ../drivers/video/fbdev/core/fbcon.c:915:3: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation] return err; ^ ../drivers/video/fbdev/core/fbcon.c:912:2: note: previous statement is here if (!search_fb_in_map(info_idx)) ^ 1 warning generated. This warning occurs because there is a space before the tab on this line. This happens on several lines in this function; normalize them so that the indentation is consistent with the Linux kernel coding style and clang no longer warns. This warning was introduced before the beginning of git history so no fixes tab. Link: https://github.com/ClangBuiltLinux/linux/issues/824 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20191218025337.35044-1-natechancellor@gmail.com

fbdev: fbmem: allow overriding the number of bootup logos

2020-01-03T13:27:40Z

Probably most useful if you want no logo at all, or if you only want one logo regardless of how many CPU cores you have. Signed-off-by: Peter Rosin Reviewed-by: Geert Uytterhoeven Cc: Jonathan Corbet Cc: Matthew Wilcox Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20190827110854.12574-3-peda@axentia.se

fbcon: Export fbcon_update_vcs

2019-06-19T09:42:39Z

I failed to spot this while compile-testing. Oops. Reported-by: kbuild test robot Fixes: 9e1467002630 ("fbcon: replace FB_EVENT_MODE_CHANGE/_ALL with direct calls") Cc: Sam Ravnborg Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Daniel Thompson Cc: Lee Jones Cc: Jingoo Han Cc: Bartlomiej Zolnierkiewicz Cc: Daniel Vetter Cc: Hans de Goede Cc: Yisheng Xie Cc: "Michał Mirosław" Cc: Peter Rosin Cc: Mikulas Patocka Cc: linux-fbdev@vger.kernel.org Cc: Gerd Hoffmann Cc: Geert Uytterhoeven Cc: Lukas Wunner Cc: dri-devel@lists.freedesktop.org Signed-off-by: Daniel Vetter Signed-off-by: Maarten Lankhorst Link: https://patchwork.freedesktop.org/patch/msgid/20190619081115.27921-1-daniel.vetter@ffwll.ch

fbcon: Document what I learned about fbcon locking

2019-06-13T08:07:09Z

It's not pretty. Signed-off-by: Daniel Vetter Reviewed-by: Sam Ravnborg Reviewed-by: Maarten Lankhorst Cc: Daniel Vetter Cc: Bartlomiej Zolnierkiewicz Cc: Hans de Goede Cc: Yisheng Xie Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-32-daniel.vetter@ffwll.ch

fbcon: Call con2fb_map functions directly

2019-06-12T18:30:39Z

These are actually fbcon ioctls which just happen to be exposed through /dev/fb*. They completely ignore which fb_info they're called on, and I think the userspace tool even hardcodes to /dev/fb0. Hence just forward the entire thing to fbcon.c wholesale. Note that this patch drops the fb_lock/unlock on the set side. Since the ioctl can operate on any fb (as passed in through con2fb.framebuffer) this is bogus. Also note that fbcon.c in general never calls fb_lock on anything, so this has been badly broken already. With this the last user of the fbcon notifier callback is gone, and we can garbage collect that too. v2: add missing uaccess.h include (alpha fails to compile otherwise), reported by kbuild. v3: Remember to also drop the #defines (Maarten) v4: Add the static inline to dummy functions. Signed-off-by: Daniel Vetter Reviewed-by: Sam Ravnborg Reviewed-by: Maarten Lankhorst Cc: Maarten Lankhorst Cc: Daniel Vetter Cc: Bartlomiej Zolnierkiewicz Cc: Hans de Goede Cc: Yisheng Xie Cc: "Michał Mirosław" Cc: Peter Rosin Cc: Mikulas Patocka Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-31-daniel.vetter@ffwll.ch

vgaswitcheroo: call fbcon_remap_all directly

2019-06-12T18:30:30Z

While at it, clean up the interface a bit and push the console locking into fbcon.c. v2: Remove now outdated comment (Lukas). v3: Forgot to add static inline to the dummy function. Acked-by: Lukas Wunner Signed-off-by: Daniel Vetter Reviewed-by: Sam Ravnborg Reviewed-by: Maarten Lankhorst Cc: Lukas Wunner Cc: David Airlie Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Sean Paul Cc: Bartlomiej Zolnierkiewicz Cc: Hans de Goede Cc: Yisheng Xie Cc: linux-fbdev@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-30-daniel.vetter@ffwll.ch

fbcon: replace FB_EVENT_MODE_CHANGE/_ALL with direct calls

2019-06-12T18:30:21Z

Create a new wrapper function for this, feels like there's some refactoring room here between the two modes. v2: backlight notifier is also interested in the mode change event, it calls lcd->set_mode, of which there are 3 implementations. Thanks to Maarten for spotting this. So we keep that. We can ditch the differentiation between mode change and all mode changes (because backlight notifier doesn't care), and we can drop the FBINFO_MISC_USEREVENT stuff too, because that's just to prevent recursion between fbmem.c and fbcon.c. While at it flatten the control flow a bit. v3: Need to add a static inline to the dummy function. v4: Add missing #include to sh_mob (Sam). Cc: Sam Ravnborg Signed-off-by: Daniel Vetter Reviewed-by: Sam Ravnborg Reviewed-by: Maarten Lankhorst Acked-by: Daniel Thompson Cc: Maarten Lankhorst Cc: Lee Jones Cc: Daniel Thompson Cc: Jingoo Han Cc: Bartlomiej Zolnierkiewicz Cc: Daniel Vetter Cc: Hans de Goede Cc: Yisheng Xie Cc: "Michał Mirosław" Cc: Peter Rosin Cc: Mikulas Patocka Cc: linux-fbdev@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-29-daniel.vetter@ffwll.ch

fbdev: remove FBINFO_MISC_USEREVENT around fb_blank

2019-06-12T18:30:06Z

With the recursion broken in the previous patch we can drop the FBINFO_MISC_USEREVENT flag around calls to fb_blank - recursion prevention was it's only job. Signed-off-by: Daniel Vetter Reviewed-by: Sam Ravnborg Reviewed-by: Maarten Lankhorst Cc: Daniel Vetter Cc: Bartlomiej Zolnierkiewicz Cc: Hans de Goede Cc: Yisheng Xie Cc: "Michał Mirosław" Cc: Peter Rosin Cc: Mikulas Patocka Cc: Rob Clark Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-27-daniel.vetter@ffwll.ch