On 25/03/2025 11:31, Thomas Zimmermann wrote:
For ease of implementation, existing line-conversion functions for 8-bit formats write each pixel individually. Optimize the performance by writing mulitple pixels in a single 32-bit store.
With the commit message typo fixed, mulitple => multiple Reviewed-by: Jocelyn Falempe <jfale...@redhat.com>
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de> --- drivers/gpu/drm/drm_format_helper.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 66137df85725..73833db28c3c 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -250,10 +250,31 @@ static __always_inline void drm_fb_xfrm_line_32to8(void *dbuf, const void *sbuf, unsigned int pixels, u32 (*xfrm_pixel)(u32)) { - u8 *dbuf8 = dbuf; + __le32 *dbuf32 = dbuf; + u8 *dbuf8; const __le32 *sbuf32 = sbuf; const __le32 *send32 = sbuf32 + pixels;+ /* write 4 pixels at once */+ send32 -= pixels & GENMASK(1, 0); + while (sbuf32 < send32) { + u32 pix[4] = { + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + }; + /* write output bytes in reverse order for little endianness */ + u32 val32 = xfrm_pixel(pix[0]) | + (xfrm_pixel(pix[1]) << 8) | + (xfrm_pixel(pix[2]) << 16) | + (xfrm_pixel(pix[3]) << 24); + *dbuf32++ = cpu_to_le32(val32); + } + send32 += pixels & GENMASK(1, 0); + + /* write trailing pixels */ + dbuf8 = (u8 __force *)dbuf32; while (sbuf32 < send32) *dbuf8++ = xfrm_pixel(le32_to_cpup(sbuf32++)); }
