kpriv/linux-hardened
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

drm/i915/gen9: fix plane_blocks_per_line on watermarks calculations

Browse source 
The confusing thing is that plane_blocks_per_line is listed as part of
the method 2 calculation but is also used for other things. We
calculated it in two different places and different ways: one inside
skl_wm_method2() and the other inside skl_compute_plane_wm(). The
skl_wm_method2() implementation is the one that matches the
specification.

With this patch we fix the skl_compute_plane_wm() calculation and just
pass it as a parameter to skl_wm_method2(). We also take care to not
modify the value of plane_bytes_per_line since we're going to rely on
it having a correct value in later patches.

This should affect the watermarks for Linear and Y-tiled.

From my analysis, it looks like the two plane_blocks_per_line
variables got out of sync on 0fda65680e, but we can't really say
that commit was a regression, it looks like just an incomplete fix.
There's always the possibility that 0fda65680e matched our
specification at that time, and then later the specification changed.

v2: Try to add a "Fixes" tag (Maarten).

Fixes: 0fda65680e ("drm/i915/skl: Update watermarks for Y tiling")
Cc: stable@vger.kernel.org
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lyude <cpaul@redhat.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1474578035-424-7-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit 7a1a8aed67)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Paulo Zanoni 2016-09-22 18:00:32 -03:00 committed by Jani Nikula
parent ccc1057477
commit cf6c525a31
1 changed files with 15 additions and 24 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

39
drivers/gpu/drm/i915/intel_pm.c
View file

@ -3494,30 +3494,14 @@ static uint32_t skl_wm_method1(uint32_t pixel_rate, uint8_t cpp, uint32_t latenc
}
static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
uint32_t horiz_pixels, uint8_t cpp,
uint64_t tiling, uint32_t latency,
uint32_t y_min_scanlines)
uint32_t latency, uint32_t plane_blocks_per_line)
{
uint32_t ret;
uint32_t plane_bytes_per_line, plane_blocks_per_line;
uint32_t wm_intermediate_val;
if (latency == 0)
return UINT_MAX;
plane_bytes_per_line = horiz_pixels * cpp;
if (tiling == I915_FORMAT_MOD_Y_TILED ||
tiling == I915_FORMAT_MOD_Yf_TILED) {
plane_bytes_per_line *= y_min_scanlines;
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
plane_blocks_per_line /= y_min_scanlines;
} else if (tiling == DRM_FORMAT_MOD_NONE) {
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
} else {
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
}
wm_intermediate_val = latency * pixel_rate;
ret = DIV_ROUND_UP(wm_intermediate_val, pipe_htotal * 1000) *
plane_blocks_per_line;
@ -3606,17 +3590,24 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
y_min_scanlines = 4;
}
plane_bytes_per_line = width * cpp;
if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {
plane_blocks_per_line =
DIV_ROUND_UP(plane_bytes_per_line * y_min_scanlines, 512);
plane_blocks_per_line /= y_min_scanlines;
} else if (fb->modifier[0] == DRM_FORMAT_MOD_NONE) {
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512)
+ 1;
} else {
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
}
method1 = skl_wm_method1(plane_pixel_rate, cpp, latency);
method2 = skl_wm_method2(plane_pixel_rate,
cstate->base.adjusted_mode.crtc_htotal,
width,
cpp,
fb->modifier[0],
latency,
y_min_scanlines);
plane_bytes_per_line = width * cpp;
plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
plane_blocks_per_line);
if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {