[Intel-gfx] xf86-video-intel: Commit 08ebde4715b87867184d42b60762cd774e151f5c breaks kernel memory manager allocation

[Wu Fengguang]

On Thu, Apr 30, 2009 at 05:01:09PM +0800, Wu Fengguang wrote:
> On Wed, Apr 22, 2009 at 08:40:05AM +0800, Zhenyu Wang wrote:
> > On 2009.04.21 20:29:26 +0800, Magnus Kessler wrote:
> > > Hi Zhenyu,
> > > 
> > > your commit 08ebde4715b87867184d42b60762cd774e151f5c to the intel video driver 
> > > breaks kernel memory allocation for me on a 64 bit platform. Reverting the 
> > > patch gets me back to a working driver. The relevant output from xorg.log is:
> > 
> > sorry, I didn't test Fengguang's patch on 64 bit system, on which his patch aims
> > to fix a compiler warning...
> > 
> > Fengguang, have you tested this on x86_64 with recent kernel? 
> > 
> > Magnus, any possible to ErrorF some debug message on why memory manager allocation
> > failed?
> 
> I used the following patch to debug this issue. Got these outputs:
> 
>         videoRam =  ~0UL / KB(1);
> OK      wfg: offset=0 end=0 next-offset=18446744073709550592
> 
>         videoRam =  INT_MAX / KB(1);
> FAIL    wfg: offset=0 end=2147483648 next-offset=2147482624
> (failed because end > next-offset, here is a tricky round-up issue)
> 
>         videoRam = 0;
>         size = ULONG_MAX;
> OK      wfg: offset=0 end=0 next-offset=18446744073709551615

This updated patch explicitly considers the align issue :-)

Thanks,
Fengguang
---
Use zero videoRam size in drm mode

Explictly set videoRam to 0 in drm mode, to indicate "no size limit".
And to use a large _aligned_ size limit for this case. Because
i830_allocate_aperture() does a testing

        if (mem->end <= scan->next->offset)
                break;

which can fail in a very tricky way when
        mem->end           = rounded up size_limit
        scan->next->offset = untouched  size_limit

Signed-off-by: Wu Fengguang <fengguang.wu at intel.com>
---
 src/i830_driver.c |    2 +-
 src/i830_memory.c |    5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

--- xf86-video-intel.orig/src/i830_driver.c
+++ xf86-video-intel/src/i830_driver.c
@@ -2550,7 +2550,7 @@ I830ScreenInit(int scrnIndex, ScreenPtr 
 
    if (pI830->use_drm_mode) {
        pI830->stolen_size = 0;
-       pScrn->videoRam = ~0UL / KB(1);
+       pScrn->videoRam = 0;
    } else {
        I830AdjustMemory(pScreen);
    }
--- xf86-video-intel.orig/src/i830_memory.c
+++ xf86-video-intel/src/i830_memory.c
@@ -394,6 +394,9 @@ i830_allocator_init(ScrnInfoPtr pScrn, u
 	return FALSE;
     }
 
+    if (size == 0) /* use_drm_mode: no size limit */
+	    size = ALIGN(ULONG_MAX/2, GTT_PAGE_SIZE);
+
     start->key = -1;
     start->offset = 0;
     start->end = start->offset;
@@ -425,7 +428,7 @@ i830_allocator_init(ScrnInfoPtr pScrn, u
      * rather than after DRIFinishScreenInit.
      */
     if (pI830->directRenderingType == DRI_DRI2 && has_gem) {
-	int mmsize;
+	unsigned long mmsize;
 
 	/* Take over all of the graphics aperture minus enough to for
 	 * physical-address allocations of cursor/overlay registers.