[Intel-gfx] [PATCH 2/2] drm/i915: load a ring frequency scaling table
Jesse Barnes
jbarnes at virtuousgeek.org
Fri Jun 24 20:13:14 CEST 2011
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.
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
drivers/gpu/drm/i915/i915_debugfs.c | 43 +++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_reg.h | 4 ++-
drivers/gpu/drm/i915/i915_suspend.c | 4 ++-
drivers/gpu/drm/i915/intel_display.c | 57 +++++++++++++++++++++++++++++++++-
drivers/gpu/drm/i915/intel_drv.h | 1 +
5 files changed, 106 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4d46441..79394cd 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1123,6 +1123,48 @@ 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;
+
+ gen6_gt_force_wake_get(dev_priv);
+
+ seq_printf(m, "GPU freq\tEffective CPU freq\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 write 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);
+ }
+
+ gen6_gt_force_wake_put(dev_priv);
+
+ 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 +1468,7 @@ 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},
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2f967af..757e024 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3433,7 +3433,9 @@
#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_ */
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 60a94d2..03f0fac 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -870,8 +870,10 @@ 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);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 86a3ec1..3b22e12 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -24,6 +24,7 @@
* Eric Anholt <eric at anholt.net>
*/
+#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
@@ -7159,6 +7160,58 @@ 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 3GHz if none found, PCU will ensure we don't go over */
+ if (!max_ia_freq)
+ max_ia_freq = 3000000;
+
+ /* Convert from kHz to MHz */
+ max_ia_freq /= 1000;
+
+ mutex_lock(&dev_priv->dev->struct_mutex);
+ gen6_gt_force_wake_get(dev_priv);
+
+ /*
+ * 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;
+ }
+ }
+
+ gen6_gt_force_wake_put(dev_priv);
+ 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;
@@ -7777,8 +7830,10 @@ 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,
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 9ffa61e..8ac3bd8 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -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);
--
1.7.4.1
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