linux-kernel - [patch] rivafb/nvidiafb: race between register_framebuffer and *_bl

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Date:	Sat, 22 Jul 2006 18:28:21 +0200
From:	Guido Guenther <agx@...xcpu.org>
To:	adaplas@...il.com
Cc:	linux-kernel@...r.kernel.org
Subject: [patch] rivafb/nvidiafb: race between register_framebuffer and *_bl_init

Hi,
Since we now use the generic backlight infrastructure, I think we need
to call rivafb_bl_init before calling register_framebuffer since
otherwise rivafb_bl_init might race with the framebuffer layer already
opening the device and setting up the video mode. In this case we might
end up with a not yet fully intialized backlight (info->bl_dev still
NULL) when calling riva_bl_set_power via
rivafb_set_par/rivafb_load_video_mode and the kernel dies without any
further notice during boot.
This fixes booting current git on a PB 6,1, please apply if it looks
correct - in this case radeonfb/atyfb would be affected too - I can fix
that too but don't have any hardware to test this on.
Cheers,
 -- Guido

diff --git a/drivers/video/nvidia/nvidia.c b/drivers/video/nvidia/nvidia.c
index 9f2066f..eae291e 100644
--- a/drivers/video/nvidia/nvidia.c
+++ b/drivers/video/nvidia/nvidia.c
@@ -1303,20 +1303,19 @@ #endif				/* CONFIG_MTRR */
 
 	nvidia_save_vga(par, &par->SavedReg);
 
+	pci_set_drvdata(pd, info);
+	nvidia_bl_init(par);
 	if (register_framebuffer(info) < 0) {
 		printk(KERN_ERR PFX "error registering nVidia framebuffer\n");
 		goto err_out_iounmap_fb;
 	}
 
-	pci_set_drvdata(pd, info);
 
 	printk(KERN_INFO PFX
 	       "PCI nVidia %s framebuffer (%dMB @ 0x%lX)\n",
 	       info->fix.id,
 	       par->FbMapSize / (1024 * 1024), info->fix.smem_start);
 
-	nvidia_bl_init(par);
-
 	NVTRACE_LEAVE();
 	return 0;
 
@@ -2132,15 +2132,17 @@ #endif /* CONFIG_MTRR */
 
 	fb_destroy_modedb(info->monspecs.modedb);
 	info->monspecs.modedb = NULL;
+
+	pci_set_drvdata(pd, info);
+	riva_bl_init(info->par);
 	ret = register_framebuffer(info);
+
 	if (ret < 0) {
 		printk(KERN_ERR PFX
 			"error registering riva framebuffer\n");
 		goto err_iounmap_screen_base;
 	}
 
-	pci_set_drvdata(pd, info);
-
 	printk(KERN_INFO PFX
 		"PCI nVidia %s framebuffer ver %s (%dMB @ 0x%lX)\n",
 		info->fix.id,
@@ -2148,8 +2150,6 @@ #endif /* CONFIG_MTRR */
 		info->fix.smem_len / (1024 * 1024),
 		info->fix.smem_start);
 
-	riva_bl_init(info->par);
-
 	NVTRACE_LEAVE();
 	return 0;
 


Signed-Off-By: Guido Guenther <agx@...xcpu.org>
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