Commit 3312ba65 authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Daniel Vetter

drm/i915: Disable specific watermark levels when latency is zero

Return UINT_MAX for the calculated WM level if the latency is zero.
This will lead to marking the WM level as disabled.

I'm not sure if latency==0 should mean that we want to disable the
level. But that's the implication I got from the fact that we don't
even enable the watermark code of the SSKDP register is 0.

v2: Use WARN() to scare people
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 26ec971e
......@@ -2131,6 +2131,9 @@ static uint32_t ilk_wm_method1(uint32_t pixel_rate, uint8_t bytes_per_pixel,
{
uint64_t ret;
if (WARN(latency == 0, "Latency value missing\n"))
return UINT_MAX;
ret = (uint64_t) pixel_rate * bytes_per_pixel * latency;
ret = DIV_ROUND_UP_ULL(ret, 64 * 10000) + 2;
......@@ -2143,6 +2146,9 @@ static uint32_t ilk_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
{
uint32_t ret;
if (WARN(latency == 0, "Latency value missing\n"))
return UINT_MAX;
ret = (latency * pixel_rate) / (pipe_htotal * 10000);
ret = (ret + 1) * horiz_pixels * bytes_per_pixel;
ret = DIV_ROUND_UP(ret, 64) + 2;
......
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