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drm/i915: support low power watermarks on Ironlake

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This patch actually makes the watermark code even uglier (if that's
possible), but has the advantage of sharing code between SNB and ILK at
least.  Longer term we should refactor the watermark stuff into its own
file and clean it up now that we know how it's supposed to work.

Supporting WM2 on my Vaio reduced power consumption by around 0.5W, so
this patch is definitely worthwhile (though it also needs lots of test
coverage).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[ickle: pass the watermark structs arounds]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Jesse Barnes 2010-12-21 13:10:23 -08:00 committed by Chris Wilson
parent c97689d886
commit b79d499022
2 changed files with 154 additions and 151 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/gpu/drm/i915/i915_reg.h
View file

@ -2345,8 +2345,13 @@
/* Memory latency timer register */
#define MLTR_ILK 0x11222
#define MLTR_WM1_SHIFT 0
#define MLTR_WM2_SHIFT 8
/* the unit of memory self-refresh latency time is 0.5us */
#define ILK_SRLT_MASK 0x3f
#define ILK_LATENCY(shift) (I915_READ(MLTR_ILK) >> (shift) & ILK_SRLT_MASK)
#define ILK_READ_WM1_LATENCY() ILK_LATENCY(MLTR_WM1_SHIFT)
#define ILK_READ_WM2_LATENCY() ILK_LATENCY(MLTR_WM2_SHIFT)
/* define the fifo size on Ironlake */
#define ILK_DISPLAY_FIFO 128

300
drivers/gpu/drm/i915/intel_display.c
View file

@ -3456,14 +3456,109 @@ static bool ironlake_compute_wm0(struct drm_device *dev,
return true;
}
/*
* Check the wm result.
*
* If any calculated watermark values is larger than the maximum value that
* can be programmed into the associated watermark register, that watermark
* must be disabled.
*/
static bool ironlake_check_srwm(struct drm_device *dev, int level,
int fbc_wm, int display_wm, int cursor_wm,
const struct intel_watermark_params *display,
const struct intel_watermark_params *cursor)
{
struct drm_i915_private *dev_priv = dev->dev_private;
DRM_DEBUG_KMS("watermark %d: display plane %d, fbc lines %d,"
" cursor %d\n", level, display_wm, fbc_wm, cursor_wm);
if (fbc_wm > SNB_FBC_MAX_SRWM) {
DRM_DEBUG_KMS("fbc watermark(%d) is too large(%d), disabling wm%d+\n",
fbc_wm, SNB_FBC_MAX_SRWM, level);
/* fbc has it's own way to disable FBC WM */
I915_WRITE(DISP_ARB_CTL,
I915_READ(DISP_ARB_CTL) | DISP_FBC_WM_DIS);
return false;
}
if (display_wm > display->max_wm) {
DRM_DEBUG_KMS("display watermark(%d) is too large(%d), disabling wm%d+\n",
display_wm, SNB_DISPLAY_MAX_SRWM, level);
return false;
}
if (cursor_wm > cursor->max_wm) {
DRM_DEBUG_KMS("cursor watermark(%d) is too large(%d), disabling wm%d+\n",
cursor_wm, SNB_CURSOR_MAX_SRWM, level);
return false;
}
if (!(fbc_wm || display_wm || cursor_wm)) {
DRM_DEBUG_KMS("latency %d is 0, disabling wm%d+\n", level, level);
return false;
}
return true;
}
/*
* Compute watermark values of WM[1-3],
*/
static bool ironlake_compute_srwm(struct drm_device *dev, int level,
int hdisplay, int htotal,
int pixel_size, int clock, int latency_ns,
const struct intel_watermark_params *display,
const struct intel_watermark_params *cursor,
int *fbc_wm, int *display_wm, int *cursor_wm)
{
unsigned long line_time_us;
int line_count, line_size;
int small, large;
int entries;
if (!latency_ns) {
*fbc_wm = *display_wm = *cursor_wm = 0;
return false;
}
line_time_us = (htotal * 1000) / clock;
line_count = (latency_ns / line_time_us + 1000) / 1000;
line_size = hdisplay * pixel_size;
/* Use the minimum of the small and large buffer method for primary */
small = ((clock * pixel_size / 1000) * latency_ns) / 1000;
large = line_count * line_size;
entries = DIV_ROUND_UP(min(small, large), display->cacheline_size);
*display_wm = entries + display->guard_size;
/*
* Spec says:
* FBC WM = ((Final Primary WM * 64) / number of bytes per line) + 2
*/
*fbc_wm = DIV_ROUND_UP(*display_wm * 64, line_size) + 2;
/* calculate the self-refresh watermark for display cursor */
entries = line_count * pixel_size * 64;
entries = DIV_ROUND_UP(entries, cursor->cacheline_size);
*cursor_wm = entries + cursor->guard_size;
return ironlake_check_srwm(dev, level,
*fbc_wm, *display_wm, *cursor_wm,
display, cursor);
}
static void ironlake_update_wm(struct drm_device *dev,
int planea_clock, int planeb_clock,
int sr_hdisplay, int sr_htotal,
int hdisplay, int htotal,
int pixel_size)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int plane_wm, cursor_wm, enabled;
int tmp;
int fbc_wm, plane_wm, cursor_wm, enabled;
int clock;
enabled = 0;
if (ironlake_compute_wm0(dev, 0,
@ -3498,152 +3593,49 @@ static void ironlake_update_wm(struct drm_device *dev,
* Calculate and update the self-refresh watermark only when one
* display plane is used.
*/
tmp = 0;
if (enabled == 1) {
unsigned long line_time_us;
int small, large, plane_fbc;
int sr_clock, entries;
int line_count, line_size;
/* Read the self-refresh latency. The unit is 0.5us */
int ilk_sr_latency = I915_READ(MLTR_ILK) & ILK_SRLT_MASK;
I915_WRITE(WM3_LP_ILK, 0);
I915_WRITE(WM2_LP_ILK, 0);
I915_WRITE(WM1_LP_ILK, 0);
sr_clock = planea_clock ? planea_clock : planeb_clock;
line_time_us = (sr_htotal * 1000) / sr_clock;
if (enabled != 1)
return;
/* Use ns/us then divide to preserve precision */
line_count = ((ilk_sr_latency * 500) / line_time_us + 1000)
/ 1000;
line_size = sr_hdisplay * pixel_size;
clock = planea_clock ? planea_clock : planeb_clock;
/* Use the minimum of the small and large buffer method for primary */
small = ((sr_clock * pixel_size / 1000) * (ilk_sr_latency * 500)) / 1000;
large = line_count * line_size;
/* WM1 */
if (!ironlake_compute_srwm(dev, 1, hdisplay, htotal, pixel_size,
clock, ILK_READ_WM1_LATENCY() * 500,
&ironlake_display_srwm_info,
&ironlake_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;
entries = DIV_ROUND_UP(min(small, large),
ironlake_display_srwm_info.cacheline_size);
I915_WRITE(WM1_LP_ILK,
WM1_LP_SR_EN |
(ILK_READ_WM1_LATENCY() << WM1_LP_LATENCY_SHIFT) |
(fbc_wm << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);
plane_fbc = entries * 64;
plane_fbc = DIV_ROUND_UP(plane_fbc, line_size);
/* WM2 */
if (!ironlake_compute_srwm(dev, 2, hdisplay, htotal, pixel_size,
clock, ILK_READ_WM2_LATENCY() * 500,
&ironlake_display_srwm_info,
&ironlake_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;
plane_wm = entries + ironlake_display_srwm_info.guard_size;
if (plane_wm > (int)ironlake_display_srwm_info.max_wm)
plane_wm = ironlake_display_srwm_info.max_wm;
/* calculate the self-refresh watermark for display cursor */
entries = line_count * pixel_size * 64;
entries = DIV_ROUND_UP(entries,
ironlake_cursor_srwm_info.cacheline_size);
cursor_wm = entries + ironlake_cursor_srwm_info.guard_size;
if (cursor_wm > (int)ironlake_cursor_srwm_info.max_wm)
cursor_wm = ironlake_cursor_srwm_info.max_wm;
/* configure watermark and enable self-refresh */
tmp = (WM1_LP_SR_EN |
(ilk_sr_latency << WM1_LP_LATENCY_SHIFT) |
(plane_fbc << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);
DRM_DEBUG_KMS("self-refresh watermark: display plane %d, fbc lines %d,"
" cursor %d\n", plane_wm, plane_fbc, cursor_wm);
}
I915_WRITE(WM1_LP_ILK, tmp);
/* XXX setup WM2 and WM3 */
}
/*
* Check the wm result.
*
* If any calculated watermark values is larger than the maximum value that
* can be programmed into the associated watermark register, that watermark
* must be disabled.
*
* Also return true if all of those watermark values is 0, which is set by
* sandybridge_compute_srwm, to indicate the latency is ZERO.
*/
static bool sandybridge_check_srwm(struct drm_device *dev, int level,
int fbc_wm, int display_wm, int cursor_wm)
{
struct drm_i915_private *dev_priv = dev->dev_private;
DRM_DEBUG_KMS("watermark %d: display plane %d, fbc lines %d,"
" cursor %d\n", level, display_wm, fbc_wm, cursor_wm);
if (fbc_wm > SNB_FBC_MAX_SRWM) {
DRM_DEBUG_KMS("fbc watermark(%d) is too large(%d), disabling wm%d+\n",
fbc_wm, SNB_FBC_MAX_SRWM, level);
/* fbc has it's own way to disable FBC WM */
I915_WRITE(DISP_ARB_CTL,
I915_READ(DISP_ARB_CTL) | DISP_FBC_WM_DIS);
return false;
}
if (display_wm > SNB_DISPLAY_MAX_SRWM) {
DRM_DEBUG_KMS("display watermark(%d) is too large(%d), disabling wm%d+\n",
display_wm, SNB_DISPLAY_MAX_SRWM, level);
return false;
}
if (cursor_wm > SNB_CURSOR_MAX_SRWM) {
DRM_DEBUG_KMS("cursor watermark(%d) is too large(%d), disabling wm%d+\n",
cursor_wm, SNB_CURSOR_MAX_SRWM, level);
return false;
}
if (!(fbc_wm || display_wm || cursor_wm)) {
DRM_DEBUG_KMS("latency %d is 0, disabling wm%d+\n", level, level);
return false;
}
return true;
}
/*
* Compute watermark values of WM[1-3],
*/
static bool sandybridge_compute_srwm(struct drm_device *dev, int level,
int hdisplay, int htotal, int pixel_size,
int clock, int latency_ns, int *fbc_wm,
int *display_wm, int *cursor_wm)
{
unsigned long line_time_us;
int small, large;
int entries;
int line_count, line_size;
if (!latency_ns) {
*fbc_wm = *display_wm = *cursor_wm = 0;
return false;
}
line_time_us = (htotal * 1000) / clock;
line_count = (latency_ns / line_time_us + 1000) / 1000;
line_size = hdisplay * pixel_size;
/* Use the minimum of the small and large buffer method for primary */
small = ((clock * pixel_size / 1000) * latency_ns) / 1000;
large = line_count * line_size;
entries = DIV_ROUND_UP(min(small, large),
sandybridge_display_srwm_info.cacheline_size);
*display_wm = entries + sandybridge_display_srwm_info.guard_size;
I915_WRITE(WM2_LP_ILK,
WM2_LP_EN |
(ILK_READ_WM2_LATENCY() << WM1_LP_LATENCY_SHIFT) |
(fbc_wm << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);
/*
* Spec said:
* FBC WM = ((Final Primary WM * 64) / number of bytes per line) + 2
* WM3 is unsupported on ILK, probably because we don't have latency
* data for that power state
*/
*fbc_wm = DIV_ROUND_UP(*display_wm * 64, line_size) + 2;
/* calculate the self-refresh watermark for display cursor */
entries = line_count * pixel_size * 64;
entries = DIV_ROUND_UP(entries,
sandybridge_cursor_srwm_info.cacheline_size);
*cursor_wm = entries + sandybridge_cursor_srwm_info.guard_size;
return sandybridge_check_srwm(dev, level,
*fbc_wm, *display_wm, *cursor_wm);
}
static void sandybridge_update_wm(struct drm_device *dev,
@ -3701,9 +3693,11 @@ static void sandybridge_update_wm(struct drm_device *dev,
clock = planea_clock ? planea_clock : planeb_clock;
/* WM1 */
if (!sandybridge_compute_srwm(dev, 1, hdisplay, htotal, pixel_size,
clock, SNB_READ_WM1_LATENCY() * 500,
&fbc_wm, &plane_wm, &cursor_wm))
if (!ironlake_compute_srwm(dev, 1, hdisplay, htotal, pixel_size,
clock, SNB_READ_WM1_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;
I915_WRITE(WM1_LP_ILK,
@ -3714,10 +3708,12 @@ static void sandybridge_update_wm(struct drm_device *dev,
cursor_wm);
/* WM2 */
if (!sandybridge_compute_srwm(dev, 2,
hdisplay, htotal, pixel_size,
clock, SNB_READ_WM2_LATENCY() * 500,
&fbc_wm, &plane_wm, &cursor_wm))
if (!ironlake_compute_srwm(dev, 2,
hdisplay, htotal, pixel_size,
clock, SNB_READ_WM2_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;
I915_WRITE(WM2_LP_ILK,
@ -3728,10 +3724,12 @@ static void sandybridge_update_wm(struct drm_device *dev,
cursor_wm);
/* WM3 */
if (!sandybridge_compute_srwm(dev, 3,
hdisplay, htotal, pixel_size,
clock, SNB_READ_WM3_LATENCY() * 500,
&fbc_wm, &plane_wm, &cursor_wm))
if (!ironlake_compute_srwm(dev, 3,
hdisplay, htotal, pixel_size,
clock, SNB_READ_WM3_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;
I915_WRITE(WM3_LP_ILK,