linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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


             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 ` 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20211111092053.1328304-1-javierm@redhat.com \
    --to=javierm@redhat.com \
    --cc=daniel.vetter@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=lahvuun@gmail.com \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sam@ravnborg.org \
    --cc=tzimmermann@suse.de \
    --subject='Re: [PATCH] fbdev: Prevent probing generic drivers if a FB is already registered' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).