From 20a7ead8bdf09774c7d58fcbe6a0980d08ed5365 Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Fri, 7 Sep 2018 22:12:26 +0300 Subject: lib: Add roundup_power_of_two() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a helper to round a value to the next power of two size. And since we need fls() to implement that, reuse that elsewhere as well. Signed-off-by: Ville Syrjälä Reviewed-by: Chris Wilson --- lib/igt_aux.h | 6 ++++++ lib/igt_fb.c | 12 ++++-------- 2 files changed, 10 insertions(+), 8 deletions(-) (limited to 'lib') diff --git a/lib/igt_aux.h b/lib/igt_aux.h index ef89faa9..192c3ad8 100644 --- a/lib/igt_aux.h +++ b/lib/igt_aux.h @@ -287,4 +287,10 @@ void igt_lsof(const char *dpath); #define is_power_of_two(x) (((x) & ((x)-1)) == 0) +#define igt_fls(x) ((x) ? __builtin_choose_expr(sizeof(x) == 8, \ + 64 - __builtin_clzll(x), \ + 32 - __builtin_clz(x)) : 0) + +#define roundup_power_of_two(x) ((x) != 0 ? 1 << igt_fls((x) - 1) : 0) + #endif /* IGT_AUX_H */ diff --git a/lib/igt_fb.c b/lib/igt_fb.c index 7c71e52a..1ba1aa7c 100644 --- a/lib/igt_fb.c +++ b/lib/igt_fb.c @@ -261,8 +261,6 @@ static void calc_fb_size_packed(int fd, int width, int height, if (tiling != LOCAL_DRM_FORMAT_MOD_NONE && intel_gen(intel_get_drm_devid(fd)) <= 3) { - int v; - /* Round the tiling up to the next power-of-two and the region * up to the next pot fence size so that this works on all * generations. @@ -271,13 +269,11 @@ static void calc_fb_size_packed(int fd, int width, int height, * tiled. But then that failure is expected. */ - v = byte_width; - for (stride = 512; stride < v; stride *= 2) - ; + stride = max(byte_width, 512); + stride = roundup_power_of_two(stride); - v = stride * height; - for (size = 1024*1024; size < v; size *= 2) - ; + size = max((uint64_t) stride * height, 1024*1024); + size = roundup_power_of_two(size); } else { stride = ALIGN(byte_width, tile_width); size = (uint64_t) stride * ALIGN(height, tile_height); -- cgit v1.2.3