drm/i915: Ensure that while(INREG()) are bounded (v2)
Add a new macro, wait_for, to simplify the act of waiting on a register
to change state. wait_for() takes three arguments, the condition to
inspect on every loop, the maximum amount of time to wait and whether to
yield the cpu for a length of time after each check.
v2: Upgrade failure messages to DRM_ERROR on the suggestion of
Eric Anholt. We do not expect to hit these conditions as they reflect
programming errors, so if we do we want to be notified.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1eae234..0bf683d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1037,7 +1037,6 @@
void i8xx_disable_fbc(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
- unsigned long timeout = jiffies + msecs_to_jiffies(1);
u32 fbc_ctl;
if (!I915_HAS_FBC(dev))
@@ -1052,12 +1051,9 @@
I915_WRITE(FBC_CONTROL, fbc_ctl);
/* Wait for compressing bit to clear */
- while (I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING) {
- if (time_after(jiffies, timeout)) {
- DRM_DEBUG_DRIVER("FBC idle timed out\n");
- break;
- }
- ; /* do nothing */
+ if (wait_for((I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING) == 0, 10, 0)) {
+ DRM_DEBUG_KMS("FBC idle timed out\n");
+ return;
}
intel_wait_for_vblank(dev);
@@ -1943,7 +1939,6 @@
int trans_vsync_reg = (pipe == 0) ? TRANS_VSYNC_A : TRANS_VSYNC_B;
int trans_dpll_sel = (pipe == 0) ? 0 : 1;
u32 temp;
- int n;
u32 pipe_bpc;
temp = I915_READ(pipeconf_reg);
@@ -2134,9 +2129,8 @@
I915_WRITE(transconf_reg, temp | TRANS_ENABLE);
I915_READ(transconf_reg);
- while ((I915_READ(transconf_reg) & TRANS_STATE_ENABLE) == 0)
- ;
-
+ if (wait_for(I915_READ(transconf_reg) & TRANS_STATE_ENABLE, 10, 0))
+ DRM_ERROR("failed to enable transcoder\n");
}
intel_crtc_load_lut(crtc);
@@ -2167,20 +2161,10 @@
temp = I915_READ(pipeconf_reg);
if ((temp & PIPEACONF_ENABLE) != 0) {
I915_WRITE(pipeconf_reg, temp & ~PIPEACONF_ENABLE);
- I915_READ(pipeconf_reg);
- n = 0;
+
/* wait for cpu pipe off, pipe state */
- while ((I915_READ(pipeconf_reg) & I965_PIPECONF_ACTIVE) != 0) {
- n++;
- if (n < 60) {
- udelay(500);
- continue;
- } else {
- DRM_DEBUG_KMS("pipe %d off delay\n",
- pipe);
- break;
- }
- }
+ if (wait_for((I915_READ(pipeconf_reg) & I965_PIPECONF_ACTIVE) == 0, 50, 1))
+ DRM_ERROR("failed to turn off cpu pipe\n");
} else
DRM_DEBUG_KMS("crtc %d is disabled\n", pipe);
@@ -2241,20 +2225,10 @@
temp = I915_READ(transconf_reg);
if ((temp & TRANS_ENABLE) != 0) {
I915_WRITE(transconf_reg, temp & ~TRANS_ENABLE);
- I915_READ(transconf_reg);
- n = 0;
+
/* wait for PCH transcoder off, transcoder state */
- while ((I915_READ(transconf_reg) & TRANS_STATE_ENABLE) != 0) {
- n++;
- if (n < 60) {
- udelay(500);
- continue;
- } else {
- DRM_DEBUG_KMS("transcoder %d off "
- "delay\n", pipe);
- break;
- }
- }
+ if (wait_for((I915_READ(transconf_reg) & TRANS_STATE_ENABLE) == 0, 50, 1))
+ DRM_ERROR("failed to disable transcoder\n");
}
temp = I915_READ(transconf_reg);
@@ -5521,7 +5495,6 @@
struct drm_i915_private *dev_priv = dev->dev_private;
u32 rgvmodectl = I915_READ(MEMMODECTL);
u8 fmax, fmin, fstart, vstart;
- int i = 0;
/* 100ms RC evaluation intervals */
I915_WRITE(RCUPEI, 100000);
@@ -5565,13 +5538,8 @@
rgvmodectl |= MEMMODE_SWMODE_EN;
I915_WRITE(MEMMODECTL, rgvmodectl);
- while (I915_READ(MEMSWCTL) & MEMCTL_CMD_STS) {
- if (i++ > 100) {
- DRM_ERROR("stuck trying to change perf mode\n");
- break;
- }
- msleep(1);
- }
+ if (wait_for((I915_READ(MEMSWCTL) & MEMCTL_CMD_STS) == 0, 1, 0))
+ DRM_ERROR("stuck trying to change perf mode\n");
msleep(1);
ironlake_set_drps(dev, fstart);