For multi-planar formats, while calculating offsets in planes with index greater than 0
(ie second plane, third plane, etc), one needs to divide (src_x * cpp) with horizontal
chroma subsampling factor and (src_y * pitch) with vertical chroma subsampling factor.
The reason being that the planes contain subsampled (ie reduced) data (by a factor of 2) and thus the
while calculating the byte position coresponding to the x and y co-ordinates, one needs to be
divide it with the sampling factor.
Signed-off-by: Ayan Kumar halder <ayan.halder@xxxxxxx>
---
drivers/gpu/drm/drm_fb_cma_helper.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
index b127061..47e0e2f 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -86,14 +86,21 @@ dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
{
struct drm_gem_cma_object *obj;
dma_addr_t paddr;
+ u8 h_div = 1, v_div = 1;
obj = drm_fb_cma_get_gem_obj(fb, plane);
if (!obj)
return 0;
paddr = obj->paddr + fb->offsets[plane];
- paddr += fb->format->cpp[plane] * (state->src_x >> 16);
- paddr += fb->pitches[plane] * (state->src_y >> 16);
+
+ if (plane > 0) {
+ h_div = fb->format->hsub;
+ v_div = fb->format->vsub;
+ }
+
+ paddr += (fb->format->cpp[plane] * (state->src_x >> 16)) / h_div;
+ paddr += (fb->pitches[plane] * (state->src_y >> 16)) / v_div;
return paddr;
}
--
2.7.4
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