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Date: Thu, 11 Nov 2021 10:20:53 +0100
From: Javier Martinez Canillas <javierm@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Sam Ravnborg <sam@...nborg.org>, linux-fbdev@...r.kernel.org,
dri-devel@...ts.freedesktop.org,
Daniel Vetter <daniel.vetter@...ll.ch>,
Thomas Zimmermann <tzimmermann@...e.de>,
Ilya Trukhanov <lahvuun@...il.com>,
Javier Martinez Canillas <javierm@...hat.com>
Subject: [PATCH] fbdev: Prevent probing generic drivers if a FB is already registered
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.
Reported-by: Ilya Trukhanov <lahvuun@...il.com>
Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
---
drivers/video/fbdev/efifb.c | 6 ++++++
drivers/video/fbdev/simplefb.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git drivers/video/fbdev/efifb.c drivers/video/fbdev/efifb.c
index edca3703b964..76325c07cf0c 100644
--- drivers/video/fbdev/efifb.c
+++ drivers/video/fbdev/efifb.c
@@ -351,6 +351,12 @@ static int efifb_probe(struct platform_device *dev)
char *option = NULL;
efi_memory_desc_t md;
+ 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..55c1f54d7663 100644
--- drivers/video/fbdev/simplefb.c
+++ drivers/video/fbdev/simplefb.c
@@ -407,6 +407,12 @@ static int simplefb_probe(struct platform_device *pdev)
struct simplefb_par *par;
struct resource *mem;
+ 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
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