| Message ID | 20211111115757.1351045-1-javierm@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] fbdev: Prevent probing generic drivers if a FB is already registered | expand |
On Thu, Nov 11, 2021 at 12:57:57PM +0100, Javier Martinez Canillas wrote: > The efifb and simplefb drivers just render to a pre-allocated frame buffer > and rely on the display hardware being initialized before the kernel boots. > > But if another driver already probed correctly and registered a fbdev, the > generic drivers shouldn't be probed since an actual driver for the display > hardware is already present. > > This is more likely to occur after commit d391c5827107 ("drivers/firmware: > move x86 Generic System Framebuffers support") since the "efi-framebuffer" > and "simple-framebuffer" platform devices are registered at a later time. > > Link: https://lore.kernel.org/r/20211110200253.rfudkt3edbd3nsyj@lahvuun/ > Fixes: d391c5827107 ("drivers/firmware: move x86 Generic System Framebuffers support") > Reported-by: Ilya Trukhanov <lahvuun@gmail.com> > Cc: <stable@vger.kernel.org> # 5.15.x > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > > Changes in v3: > - Cc <stable@vger.kernel.org> since a Fixes: tag is not enough (gregkh). > > Changes in v2: > - Add a Link: tag with a reference to the bug report (Thorsten Leemhuis). > - Add a comment explaining why the probe fails earlier (Daniel Vetter). > - Add a Fixes: tag for stable to pick the fix (Daniel Vetter). > - Add Daniel Vetter's Reviewed-by: tag. > - Improve the commit message and mention the culprit commit > > drivers/video/fbdev/efifb.c | 11 +++++++++++ > drivers/video/fbdev/simplefb.c | 11 +++++++++++ > 2 files changed, 22 insertions(+) > > diff --git drivers/video/fbdev/efifb.c drivers/video/fbdev/efifb.c > index edca3703b964..ea42ba6445b2 100644 > --- drivers/video/fbdev/efifb.c > +++ drivers/video/fbdev/efifb.c > @@ -351,6 +351,17 @@ static int efifb_probe(struct platform_device *dev) > char *option = NULL; > efi_memory_desc_t md; > > + /* > + * Generic drivers must not be registered if a framebuffer exists. > + * If a native driver was probed, the display hardware was already > + * taken and attempting to use the system framebuffer is dangerous. > + */ > + if (num_registered_fb > 0) { > + dev_err(&dev->dev, > + "efifb: a framebuffer is already registered\n"); > + return -EINVAL; > + } > + > if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled) > return -ENODEV; > > diff --git drivers/video/fbdev/simplefb.c drivers/video/fbdev/simplefb.c > index 62f0ded70681..b63074fd892e 100644 > --- drivers/video/fbdev/simplefb.c > +++ drivers/video/fbdev/simplefb.c > @@ -407,6 +407,17 @@ static int simplefb_probe(struct platform_device *pdev) > struct simplefb_par *par; > struct resource *mem; > > + /* > + * Generic drivers must not be registered if a framebuffer exists. > + * If a native driver was probed, the display hardware was already > + * taken and attempting to use the system framebuffer is dangerous. > + */ > + if (num_registered_fb > 0) { > + dev_err(&pdev->dev, > + "simplefb: a framebuffer is already registered\n"); > + return -EINVAL; > + } > + > if (fb_get_options("simplefb", NULL)) > return -ENODEV; > > -- > 2.33.1 > This patch fixes the suspend issue I was experiencing. Thank you. Tested-by: Ilya Trukhanov <lahvuun@gmail.com>
diff --git drivers/video/fbdev/efifb.c drivers/video/fbdev/efifb.c index edca3703b964..ea42ba6445b2 100644 --- drivers/video/fbdev/efifb.c +++ drivers/video/fbdev/efifb.c @@ -351,6 +351,17 @@ static int efifb_probe(struct platform_device *dev) char *option = NULL; efi_memory_desc_t md; + /* + * Generic drivers must not be registered if a framebuffer exists. + * If a native driver was probed, the display hardware was already + * taken and attempting to use the system framebuffer is dangerous. + */ + if (num_registered_fb > 0) { + dev_err(&dev->dev, + "efifb: a framebuffer is already registered\n"); + return -EINVAL; + } + if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled) return -ENODEV; diff --git drivers/video/fbdev/simplefb.c drivers/video/fbdev/simplefb.c index 62f0ded70681..b63074fd892e 100644 --- drivers/video/fbdev/simplefb.c +++ drivers/video/fbdev/simplefb.c @@ -407,6 +407,17 @@ static int simplefb_probe(struct platform_device *pdev) struct simplefb_par *par; struct resource *mem; + /* + * Generic drivers must not be registered if a framebuffer exists. + * If a native driver was probed, the display hardware was already + * taken and attempting to use the system framebuffer is dangerous. + */ + if (num_registered_fb > 0) { + dev_err(&pdev->dev, + "simplefb: a framebuffer is already registered\n"); + return -EINVAL; + } + if (fb_get_options("simplefb", NULL)) return -ENODEV;
The efifb and simplefb drivers just render to a pre-allocated frame buffer and rely on the display hardware being initialized before the kernel boots. But if another driver already probed correctly and registered a fbdev, the generic drivers shouldn't be probed since an actual driver for the display hardware is already present. This is more likely to occur after commit d391c5827107 ("drivers/firmware: move x86 Generic System Framebuffers support") since the "efi-framebuffer" and "simple-framebuffer" platform devices are registered at a later time. Link: https://lore.kernel.org/r/20211110200253.rfudkt3edbd3nsyj@lahvuun/ Fixes: d391c5827107 ("drivers/firmware: move x86 Generic System Framebuffers support") Reported-by: Ilya Trukhanov <lahvuun@gmail.com> Cc: <stable@vger.kernel.org> # 5.15.x Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> --- Changes in v3: - Cc <stable@vger.kernel.org> since a Fixes: tag is not enough (gregkh). Changes in v2: - Add a Link: tag with a reference to the bug report (Thorsten Leemhuis). - Add a comment explaining why the probe fails earlier (Daniel Vetter). - Add a Fixes: tag for stable to pick the fix (Daniel Vetter). - Add Daniel Vetter's Reviewed-by: tag. - Improve the commit message and mention the culprit commit drivers/video/fbdev/efifb.c | 11 +++++++++++ drivers/video/fbdev/simplefb.c | 11 +++++++++++ 2 files changed, 22 insertions(+)