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Subject[PATCH 6/8] omapfb: Condition mutex acquisition
From
Date
From: Sergio Aguirre <saaguirre@ti.com>

This fixes a bug introduced by this commit ID:

commit 537a1bf059fa312355696fa6db80726e655e7f17
Author: Krzysztof Helt <krzysztof.h1@wp.pl>
Date: Tue Jun 30 11:41:29 2009 -0700

fbdev: add mutex for fb_mmap locking

In which a mutex was added when changing smem_start and smem_len fields,
so the mutex inside the fb_mmap() call is actually used.

The problem was that set_fb_fix, which modifies the above 2 fields,
was called before and after registering the framebuffer,
which when used before registration, lead to a failed attempt to
use an uninitialized mutex.

Solution: Don't use mutex before framebuffer registration.

Signed-off-by: Sergio Aguirre <saaguirre@ti.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Acked-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
drivers/video/omap/omapfb_main.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/video/omap/omapfb_main.c b/drivers/video/omap/omapfb_main.c
index 125e605..0d0c8c8 100644
--- a/drivers/video/omap/omapfb_main.c
+++ b/drivers/video/omap/omapfb_main.c
@@ -393,7 +393,7 @@ static void omapfb_sync(struct fb_info *fbi)
* Set fb_info.fix fields and also updates fbdev.
* When calling this fb_info.var must be set up already.
*/
-static void set_fb_fix(struct fb_info *fbi)
+static void set_fb_fix(struct fb_info *fbi, int from_init)
{
struct fb_fix_screeninfo *fix = &fbi->fix;
struct fb_var_screeninfo *var = &fbi->var;
@@ -403,10 +403,16 @@ static void set_fb_fix(struct fb_info *fbi)

rg = &plane->fbdev->mem_desc.region[plane->idx];
fbi->screen_base = rg->vaddr;
- mutex_lock(&fbi->mm_lock);
- fix->smem_start = rg->paddr;
- fix->smem_len = rg->size;
- mutex_unlock(&fbi->mm_lock);
+
+ if (!from_init) {
+ mutex_lock(&fbi->mm_lock);
+ fix->smem_start = rg->paddr;
+ fix->smem_len = rg->size;
+ mutex_unlock(&fbi->mm_lock);
+ } else {
+ fix->smem_start = rg->paddr;
+ fix->smem_len = rg->size;
+ }

fix->type = FB_TYPE_PACKED_PIXELS;
bpp = var->bits_per_pixel;
@@ -704,7 +710,7 @@ static int omapfb_set_par(struct fb_info *fbi)
int r = 0;

omapfb_rqueue_lock(fbdev);
- set_fb_fix(fbi);
+ set_fb_fix(fbi, 0);
r = ctrl_change_mode(fbi);
omapfb_rqueue_unlock(fbdev);

@@ -904,7 +910,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct omapfb_mem_info *mi)
if (old_size != size) {
if (size) {
memcpy(&fbi->var, new_var, sizeof(fbi->var));
- set_fb_fix(fbi);
+ set_fb_fix(fbi, 0);
} else {
/*
* Set these explicitly to indicate that the
@@ -1504,7 +1510,7 @@ static int fbinfo_init(struct omapfb_device *fbdev, struct fb_info *info)
var->bits_per_pixel = fbdev->panel->bpp;

set_fb_var(info, var);
- set_fb_fix(info);
+ set_fb_fix(info, 1);

r = fb_alloc_cmap(&info->cmap, 16, 0);
if (r != 0)


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