| Message ID | 20200912190301.490297-1-rikard.falkeborn@gmail.com |
|---|---|
| State | Accepted |
| Commit | 927e78ac8bc58155316cf6f46026e1912bbbbcfc |
| Headers | show |
| Series | media: venus: helpers: Fix ALIGN() of non power of two | expand |
diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c index 7147871d9dc1..194c5dd08803 100644 --- a/drivers/media/platform/qcom/venus/helpers.c +++ b/drivers/media/platform/qcom/venus/helpers.c @@ -678,8 +678,8 @@ static u32 get_framesize_raw_yuv420_tp10_ubwc(u32 width, u32 height) u32 extradata = SZ_16K; u32 size; - y_stride = ALIGN(ALIGN(width, 192) * 4 / 3, 256); - uv_stride = ALIGN(ALIGN(width, 192) * 4 / 3, 256); + y_stride = ALIGN(width * 4 / 3, 256); + uv_stride = ALIGN(width * 4 / 3, 256); y_sclines = ALIGN(height, 16); uv_sclines = ALIGN((height + 1) >> 1, 16);
ALIGN() expects its second argument to be a power of 2, otherwise incorrect results are produced for some inputs. The output can be both larger or smaller than what is expected. For example, ALIGN(304, 192) equals 320 instead of 384, and ALIGN(65, 192) equals 256 instead of 192. However, nestling two ALIGN() as is done in this case seem to only produce results equal to or bigger than the expected result if ALIGN() had handled non powers of two, and that in turn results in framesizes that are either the correct size or too large. Fortunately, since 192 * 4 / 3 equals 256, it turns out that one ALIGN() is sufficient. Fixes: ab1eda449c6e ("media: venus: vdec: handle 10bit bitstreams") Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com> --- I'm fairly certain this patch does the right thing, but I have only compile-tested it (I don't have the hardware to test on). The only reason I spotted it is that I tried implementing compile-time checking of arguments to ALIGN (and some other functions) to check that arguments that are supposed to be powers of two really are powers of two, and it found this. drivers/media/platform/qcom/venus/helpers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)