From: Javier Martinez Canillas <javierm@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Sam Ravnborg <sam@ravnborg.org>,
linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Thomas Zimmermann <tzimmermann@suse.de>,
Ilya Trukhanov <lahvuun@gmail.com>,
Javier Martinez Canillas <javierm@redhat.com>
Subject: [PATCH] fbdev: Prevent probing generic drivers if a FB is already registered
Date: Thu, 11 Nov 2021 10:20:53 +0100 [thread overview]
Message-ID: <20211111092053.1328304-1-javierm@redhat.com> (raw)
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@gmail.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.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
next reply other threads:[~2021-11-11 9:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-11 9:20 Javier Martinez Canillas [this message]
2021-11-11 9:54 ` [PATCH] fbdev: Prevent probing generic drivers if a FB is already registered Daniel Vetter
2021-11-11 11:18 ` Javier Martinez Canillas
2021-11-11 9:58 ` Thorsten Leemhuis
2021-11-11 10:00 ` Daniel Vetter
2021-11-11 10:25 ` Thorsten Leemhuis
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