On Tue, Jan 29, 2013 at 10:40 PM, Aaron Plattner aplattner@nvidia.com wrote:
On 01/28/2013 05:38 AM, Rahul Sharma wrote:
It fixes the issue arises due to passing 'nr_pages' in place of 'nents' to sg_alloc_table. When ARM_HAS_SG_CHAIN is disabled, it is causing failure in creating SG table for the buffers having more than 204 physical pages i.e. equal to SG_MAX_SINGLE_ALLOC.
When using sg_alloc_table_from_pages interface, in place of sg_alloc_table, page list will be passes to get each contiguous section which is represented by a single entry in the table. For a Contiguous Buffer, number of entries should be equal to 1.
Following check is causing the failure which is not applicable for Non-Contig buffers:
if (WARN_ON_ONCE(nents > max_ents)) return -EINVAL;Above patch is well tested for EXYNOS4 and EXYNOS5 for with/wihtout IOMMU supprot. NOUVEAU and RADEON platforms also depends on drm_prime_pages_to_sg helper function.
This set is base on "exynos-drm-fixes" branch at http://git.kernel.org/?p=linux/kernel/git/daeinki/drm-exynos.git
Signed-off-by: Rahul Sharma rahul.sharma@samsung.com
Reviewed-by: Aaron Plattner aplattner@nvidia.com
I also verified that this reduces my 2025-entry sg_table to 6 entries, so
Tested-by: Aaron Plattner aplattner@nvidia.com
-- Aaron
Thanks Aaron,
I want to request stake-holders to review and test this patch for other platforms.
regards, Rahul Sharma.
drivers/gpu/drm/drm_prime.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7f12573..072ee08 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -217,21 +217,17 @@ int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages) { struct sg_table *sg = NULL;
struct scatterlist *iter;int i; int ret; sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); if (!sg) goto out;ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL);
ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,nr_pages << PAGE_SHIFT, GFP_KERNEL); if (ret) goto out;
for_each_sg(sg->sgl, iter, nr_pages, i)sg_set_page(iter, pages[i], PAGE_SIZE, 0);return sg;
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