From 3312ba65caa23cf1210cc578755babc394769843 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 1 Aug 2013 16:18:53 +0300 Subject: [PATCH] drm/i915: Disable specific watermark levels when latency is zero MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Ville Syrjälä Reviewed-by: Paulo Zanoni Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_pm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 8358d73ae468..856c094a35e0 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -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;