[PATCH] drm/radeon/kms: forbid big bo allocation (fdo 31708) v3

[Michel Dänzer]

On Don, 2010-12-09 at 20:19 +1000, Dave Airlie wrote: 
> 2010/12/9 Michel Dänzer <michel at daenzer.net>:
> > On Fre, 2010-12-03 at 16:38 -0500, jglisse at redhat.com wrote:
> >> From: Jerome Glisse <jglisse at redhat.com>
> >>
> >> Forbid allocating buffer bigger than visible VRAM or GTT, also
> >> properly set lpfn field.
> >>
> >> v2 - use max macro
> >>    - silence warning
> >> v3 - don't explicitly set range limit
> >>    - use min macro
> >>
> >> Cc: stable <stable at kernel.org>
> >>
> >> Signed-off-by: Jerome Glisse <jglisse at redhat.com>
> >> ---
> >>  drivers/gpu/drm/radeon/radeon_object.c |   13 +++++++++++--
> >>  1 files changed, 11 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
> >> index 1d06774..a598d00 100644
> >> --- a/drivers/gpu/drm/radeon/radeon_object.c
> >> +++ b/drivers/gpu/drm/radeon/radeon_object.c
> >> @@ -104,6 +105,14 @@ int radeon_bo_create(struct radeon_device *rdev, struct drm_gem_object *gobj,
> >>       }
> >>       *bo_ptr = NULL;
> >>
> >> +     /* maximun bo size is the minimun btw visible vram and gtt size */
> >> +     max_size = min(rdev->mc.visible_vram_size, rdev->mc.gtt_size);
> >> +     if ((page_align << PAGE_SHIFT) >= max_size) {
> >> +             printk(KERN_WARNING "%s:%d alloc size %ldM bigger than %ldMb limit\n",
> >> +                     __func__, __LINE__, page_align  >> (20 - PAGE_SHIFT), max_size >> 20);
> >> +             return -ENOMEM;
> >> +     }
> >
> > Still not sure this simple minimum is quite the right solution... e.g.
> > if GTT is larger than visible VRAM, what's the problem with having a BO
> > that fits in GTT but not in visible VRAM? On systems with 8 MB of VRAM,
> > this will effectively limit the maximum texture size to 2048x1024.
> 
> Just wondering if such a card exists, the only 8MB cards I know are
> pre-r100, I think a 16MB M6 is the lowest one I can find.

From r100_vram_init_sizes():

                rdev->mc.real_vram_size = RREG32(RADEON_CONFIG_MEMSIZE);
                /* Some production boards of m6 will report 0
                 * if it's 8 MB
                 */
                if (rdev->mc.real_vram_size == 0) {
                        rdev->mc.real_vram_size = 8192 * 1024;
                        WREG32(RADEON_CONFIG_MEMSIZE, rdev->mc.real_vram_size);
                }


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer