On Thu, Mar 06, 2008 at 02:39:24PM +0530, Sriram Neelakandan wrote:
> Hi all,
>
>
> I think i have found the root cause of all the problems
>
> In dfb_fbdev_set_mode called from primaryInitLayer (fbdev.c1108) as
>
> Listing from fdbdev.c : 1102
>
> tmp.format = DSPF_RGB16;
> tmp.buffermode = DLBM_FRONTONLY;
> tmp.source.x = 0;
> tmp.source.y = 0;
> tmp.source.w = config->width;
> tmp.source.h = config->height;
> if (dfb_fbdev_set_mode( NULL, NULL, &tmp ))
>
> NOTE: config->width & height have been setup in tmp.source.w & tmp.source.h
>
> But the code inside dfb_fbdev_set_mode (Line fbdev.c:1647)
>
> vxres = config->width;
> vyres = config->height;
>
> var.xoffset = source->x;
> var.yoffset = source->y;
>
> uses config->width & height for vxres & vyres !
>
> Please note that "config", which is "tmp" in the caller has width & height
> uninitialized.
> But only tmp.source.w & h initialized.
>
> This was the reason for the huge vxres & vyres values,
Yes, that looks like a genuine bug.
> which led to the KERNEL PANIC
I don't think that should happen even if you pass totally bogus stuff to
the ioctls(). It seems i810fb doesn't properly check some of the input.
You might want to report the oops to the fbdev-devel list and/or file
a bug in the kernel bugzilla. I have a feeling i810fb isn't actively
maintained these days but at least it's good to have a record of such
bugs.
> It was also the reason for the SurfaceCreate failure
>
> I donot know what is the right way to call this API...but changing the lines
> to this fixes the issues
>
> vxres = source->w;
> vyres = source->h;
>
> i have attached a patch for tracking the exact change.
> Please accept the patch in case if required.
The correct way to fix this would be to initialize tmp.width and
tmp.height in primaryInitLayer(). They specify the virtual resolution
whereas source.w/h specify the size of the visible part. I made a patch
but I can only compile test it right now. Here it is:
diff --git a/systems/fbdev/fbdev.c b/systems/fbdev/fbdev.c
index ba6dd74..4096c39 100644
--- a/systems/fbdev/fbdev.c
+++ b/systems/fbdev/fbdev.c
@@ -1098,7 +1098,10 @@ primaryInitLayer( CoreLayer *layer,
config->buffermode = DLBM_FRONTONLY;
config->width = default_mode->xres;
config->height = default_mode->yres;
-
+
+ memset( &tmp, 0, sizeof(CoreLayerRegionConfig) );
+ tmp.width = config->width;
+ tmp.height = config->height;
tmp.format = DSPF_RGB16;
tmp.buffermode = DLBM_FRONTONLY;
tmp.source.x = 0;
--
Ville Syrjälä
[EMAIL PROTECTED]
http://www.sci.fi/~syrjala/
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