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drm/i915: load a ring frequency scaling table v3

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The ring frequency scaling table tells the PCU to treat certain GPU
frequencies as if they were a given CPU frequency for purposes of
scaling the ring frequency.  Normally the PCU will scale the ring
frequency based on the CPU P-state, but with the table present, it will
also take the GPU frequency into account.

The main downside of keeping the ring frequency high while the CPU is
at a low frequency (or asleep altogether) is increased power
consumption.  But then if you're keeping your GPU busy, you probably
want the extra performance.

v2:
  - add units to debug table header (from Eric)
  - use tsc_khz as a fallback if the cpufreq driver doesn't give us a freq
    (from Chris)
v3:
  - fix comments & debug output
  - remove unneeded force wake get/put

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Tested-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Jesse Barnes 2011-06-28 13:04:16 -07:00 committed by Keith Packard
parent 3d73710880
commit 23b2f8bb92
5 changed files with 103 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

39
drivers/gpu/drm/i915/i915_debugfs.c
View file

@ -1123,6 +1123,44 @@ static int i915_emon_status(struct seq_file *m, void *unused)
return 0;
}
static int i915_ring_freq_table(struct seq_file *m, void *unused)
{
struct drm_info_node *node = (struct drm_info_node *) m->private;
struct drm_device *dev = node->minor->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
int ret;
int gpu_freq, ia_freq;
if (!IS_GEN6(dev)) {
seq_printf(m, "unsupported on this chipset\n");
return 0;
}
ret = mutex_lock_interruptible(&dev->struct_mutex);
if (ret)
return ret;
seq_printf(m, "GPU freq (MHz)\tEffective CPU freq (MHz)\n");
for (gpu_freq = dev_priv->min_delay; gpu_freq <= dev_priv->max_delay;
gpu_freq++) {
I915_WRITE(GEN6_PCODE_DATA, gpu_freq);
I915_WRITE(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY |
GEN6_PCODE_READ_MIN_FREQ_TABLE);
if (wait_for((I915_READ(GEN6_PCODE_MAILBOX) &
GEN6_PCODE_READY) == 0, 10)) {
DRM_ERROR("pcode read of freq table timed out\n");
continue;
}
ia_freq = I915_READ(GEN6_PCODE_DATA);
seq_printf(m, "%d\t\t%d\n", gpu_freq * 50, ia_freq * 100);
}
mutex_unlock(&dev->struct_mutex);
return 0;
}
static int i915_gfxec(struct seq_file *m, void *unused)
{
struct drm_info_node *node = (struct drm_info_node *) m->private;
@ -1426,6 +1464,7 @@ static struct drm_info_list i915_debugfs_list[] = {
{"i915_inttoext_table", i915_inttoext_table, 0},
{"i915_drpc_info", i915_drpc_info, 0},
{"i915_emon_status", i915_emon_status, 0},
{"i915_ring_freq_table", i915_ring_freq_table, 0},
{"i915_gfxec", i915_gfxec, 0},
{"i915_fbc_status", i915_fbc_status, 0},
{"i915_sr_status", i915_sr_status, 0},

4
drivers/gpu/drm/i915/i915_reg.h
View file

@ -3434,7 +3434,9 @@
#define GEN6_PCODE_MAILBOX 0x138124
#define GEN6_PCODE_READY (1<<31)
#define GEN6_READ_OC_PARAMS 0xc
#define GEN6_PCODE_WRITE_MIN_FREQ_TABLE 0x9
#define GEN6_PCODE_WRITE_MIN_FREQ_TABLE 0x8
#define GEN6_PCODE_READ_MIN_FREQ_TABLE 0x9
#define GEN6_PCODE_DATA 0x138128
#define GEN6_PCODE_FREQ_IA_RATIO_SHIFT 8
#endif /* _I915_REG_H_ */

4
drivers/gpu/drm/i915/i915_suspend.c
View file

@ -875,8 +875,10 @@ int i915_restore_state(struct drm_device *dev)
intel_init_emon(dev);
}
if (IS_GEN6(dev))
if (IS_GEN6(dev)) {
gen6_enable_rps(dev_priv);
gen6_update_ring_freq(dev_priv);
}
/* Cache mode state */
I915_WRITE (CACHE_MODE_0, dev_priv->saveCACHE_MODE_0 | 0xffff0000);

58
drivers/gpu/drm/i915/intel_display.c
View file

@ -24,6 +24,7 @@
* Eric Anholt <eric@anholt.net>
*/
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
@ -7273,6 +7274,59 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
mutex_unlock(&dev_priv->dev->struct_mutex);
}
void gen6_update_ring_freq(struct drm_i915_private *dev_priv)
{
int min_freq = 15;
int gpu_freq, ia_freq, max_ia_freq;
int scaling_factor = 180;
max_ia_freq = cpufreq_quick_get_max(0);
/*
* Default to measured freq if none found, PCU will ensure we don't go
* over
*/
if (!max_ia_freq)
max_ia_freq = tsc_khz;
/* Convert from kHz to MHz */
max_ia_freq /= 1000;
mutex_lock(&dev_priv->dev->struct_mutex);
/*
* For each potential GPU frequency, load a ring frequency we'd like
* to use for memory access. We do this by specifying the IA frequency
* the PCU should use as a reference to determine the ring frequency.
*/
for (gpu_freq = dev_priv->max_delay; gpu_freq >= dev_priv->min_delay;
gpu_freq--) {
int diff = dev_priv->max_delay - gpu_freq;
/*
* For GPU frequencies less than 750MHz, just use the lowest
* ring freq.
*/
if (gpu_freq < min_freq)
ia_freq = 800;
else
ia_freq = max_ia_freq - ((diff * scaling_factor) / 2);
ia_freq = DIV_ROUND_CLOSEST(ia_freq, 100);
I915_WRITE(GEN6_PCODE_DATA,
(ia_freq << GEN6_PCODE_FREQ_IA_RATIO_SHIFT) |
gpu_freq);
I915_WRITE(GEN6_PCODE_MAILBOX, GEN6_PCODE_READY |
GEN6_PCODE_WRITE_MIN_FREQ_TABLE);
if (wait_for((I915_READ(GEN6_PCODE_MAILBOX) &
GEN6_PCODE_READY) == 0, 10)) {
DRM_ERROR("pcode write of freq table timed out\n");
continue;
}
}
mutex_unlock(&dev_priv->dev->struct_mutex);
}
static void ironlake_init_clock_gating(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@ -7916,8 +7970,10 @@ void intel_modeset_init(struct drm_device *dev)
intel_init_emon(dev);
}
if (IS_GEN6(dev))
if (IS_GEN6(dev)) {
gen6_enable_rps(dev_priv);
gen6_update_ring_freq(dev_priv);
}
INIT_WORK(&dev_priv->idle_work, intel_idle_update);
setup_timer(&dev_priv->idle_timer, intel_gpu_idle_timer,

1
drivers/gpu/drm/i915/intel_drv.h
View file

@ -317,6 +317,7 @@ extern void intel_enable_clock_gating(struct drm_device *dev);
extern void ironlake_enable_drps(struct drm_device *dev);
extern void ironlake_disable_drps(struct drm_device *dev);
extern void gen6_enable_rps(struct drm_i915_private *dev_priv);
extern void gen6_update_ring_freq(struct drm_i915_private *dev_priv);
extern void gen6_disable_rps(struct drm_device *dev);
extern void intel_init_emon(struct drm_device *dev);