Hi Tomi,
On Thursday 18 May 2017 14:34:09 Tomi Valkeinen wrote:
> On 18/05/17 14:25, Laurent Pinchart wrote:
> > On Thursday 18 May 2017 14:14:35 Tomi Valkeinen wrote:
> >> On 18/05/17 13:59, Laurent Pinchart wrote:
> >>> On Thursday 18 May 2017 13:28:26 Tomi Valkeinen wrote:
> >>>> omap_gem uses page alignment for buffer stride. The related
> >>>> calculations
> >>>> are a bit off, though, as byte stride of 4096 gets aligned to 8192,
> >>>> instead of 4096. This patch fixes those calculations.
> >>>>
> >>>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> >>>> ---
> >>>>
> >>>> drivers/gpu/drm/omapdrm/omap_gem.c | 4 ++--
> >>>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c
> >>>> b/drivers/gpu/drm/omapdrm/omap_gem.c index 13abf221d153..4c41000ff4c4
> >>>> 100644
> >>>> --- a/drivers/gpu/drm/omapdrm/omap_gem.c
> >>>> +++ b/drivers/gpu/drm/omapdrm/omap_gem.c
> >>>> @@ -182,7 +182,7 @@ static void evict_entry(struct drm_gem_object *obj,
> >>>> size_t size = PAGE_SIZE * n;
> >>>> loff_t off = mmap_offset(obj) +
> >>>> (entry->obj_pgoff << PAGE_SHIFT);
> >>>> - const int m = 1 + ((omap_obj->width << fmt) / PAGE_SIZE);
> >>>> + const int m = 1 + (((omap_obj->width - 1) << fmt) /
> >>>> PAGE_SIZE);
> >>>
> >>> How about
> >>>
> >>> int m = round_up(omap_obj->width << fmt, PAGE_SIZE);
> >>>
> >>> instead of open-coding it ? I find that a bit easier to understand.
> >>
> >> That should be:
> >>
> >> round_up(omap_obj->width << fmt, PAGE_SIZE) / PAGE_SIZE;
> >
> > Sorry, I meant DIV_ROUND_UP, not round_up.
>
> Ah, of course. Not my day... =)
>
> From: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Date: Thu, 18 May 2017 11:51:51 +0300
> Subject: [PATCH] drm/omap: fix tiled buffer stride calculations
>
> omap_gem uses page alignment for buffer stride. The related calculations
> are a bit off, though, as byte stride of 4096 gets aligned to 8192,
> instead of 4096.
>
> This patch changes the code to use DIV_ROUND_UP(), which fixes those
> calculations and makes them more readable.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c
> b/drivers/gpu/drm/omapdrm/omap_gem.c index 13abf221d153..5c5c86ddd6f4
> 100644
> --- a/drivers/gpu/drm/omapdrm/omap_gem.c
> +++ b/drivers/gpu/drm/omapdrm/omap_gem.c
> @@ -182,7 +182,7 @@ static void evict_entry(struct drm_gem_object *obj,
> size_t size = PAGE_SIZE * n;
> loff_t off = mmap_offset(obj) +
> (entry->obj_pgoff << PAGE_SHIFT);
> - const int m = 1 + ((omap_obj->width << fmt) / PAGE_SIZE);
> + const int m = DIV_ROUND_UP(omap_obj->width << fmt, PAGE_SIZE);
>
> if (m > 1) {
> int i;
> @@ -424,7 +424,7 @@ static int fault_2d(struct drm_gem_object *obj,
> * into account in some of the math, so figure out virtual stride
> * in pages
> */
> - const int m = 1 + ((omap_obj->width << fmt) / PAGE_SIZE);
> + const int m = DIV_ROUND_UP(omap_obj->width << fmt, PAGE_SIZE);
>
> /* We don't use vmf->pgoff since that has the fake offset: */
> pgoff = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
--
Regards,
Laurent Pinchart
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