msm: kgsl: Ensure glitch free changing of the GPU frequency
If there are requests to skip levels while the clocks are on
be sure to hit the intermediate frequencies.
Change-Id: Ib69bcbc7eb87532c090b4ede28d967e4cd0f08ec
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_pwrctrl.c b/drivers/gpu/msm/kgsl_pwrctrl.c
index 7c451a9..0c2f3bf 100644
--- a/drivers/gpu/msm/kgsl_pwrctrl.c
+++ b/drivers/gpu/msm/kgsl_pwrctrl.c
@@ -64,6 +64,9 @@
new_level >= pwr->thermal_pwrlevel &&
new_level != pwr->active_pwrlevel) {
struct kgsl_pwrlevel *pwrlevel = &pwr->pwrlevels[new_level];
+ int diff = new_level - pwr->active_pwrlevel;
+ int d = (diff > 0) ? 1 : -1;
+ int level = pwr->active_pwrlevel;
pwr->active_pwrlevel = new_level;
if ((test_bit(KGSL_PWRFLAGS_CLK_ON, &pwr->power_flags)) ||
(device->state == KGSL_STATE_NAP)) {
@@ -75,7 +78,14 @@
if (pwr->idle_needed == true)
device->ftbl->idle(device,
KGSL_TIMEOUT_DEFAULT);
- clk_set_rate(pwr->grp_clks[0], pwrlevel->gpu_freq);
+ /* Don't shift by more than one level at a time to
+ * avoid glitches.
+ */
+ while (level != new_level) {
+ level += d;
+ clk_set_rate(pwr->grp_clks[0],
+ pwr->pwrlevels[level].gpu_freq);
+ }
}
if (test_bit(KGSL_PWRFLAGS_AXI_ON, &pwr->power_flags)) {
if (pwr->pcl)