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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2015-07-15 09:50:42 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-16 20:52:09 -0700 |
| commit | 7f62822ffdb19561d89f9da7956d125f95300eed (patch) | |
| tree | e33a8c4584269803ae50a7ab3b44132dc3c788ab /drivers/gpu/drm/i915/i915_drv.h | |
| parent | 57689a9f86b856fcdfd3102cb95b7e930856524a (diff) | |
| download | lwn-7f62822ffdb19561d89f9da7956d125f95300eed.tar.gz lwn-7f62822ffdb19561d89f9da7956d125f95300eed.zip | |
drm/i915: Replace WARN inside I915_READ64_2x32 with retry loop
commit ee0a227b7ac6e75f28e10269f81c7ec6eb600952 upstream.
Since we may conceivably encounter situations where the upper part of the
64bit register changes between reads, for example when a timestamp
counter overflows, change the WARN into a retry loop.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_drv.h')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.h | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 8ae6f7f06b3a..683a9b004c11 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3190,15 +3190,14 @@ int intel_freq_opcode(struct drm_i915_private *dev_priv, int val); #define I915_READ64(reg) dev_priv->uncore.funcs.mmio_readq(dev_priv, (reg), true) #define I915_READ64_2x32(lower_reg, upper_reg) ({ \ - u32 upper = I915_READ(upper_reg); \ - u32 lower = I915_READ(lower_reg); \ - u32 tmp = I915_READ(upper_reg); \ - if (upper != tmp) { \ - upper = tmp; \ - lower = I915_READ(lower_reg); \ - WARN_ON(I915_READ(upper_reg) != upper); \ - } \ - (u64)upper << 32 | lower; }) + u32 upper, lower, tmp; \ + tmp = I915_READ(upper_reg); \ + do { \ + upper = tmp; \ + lower = I915_READ(lower_reg); \ + tmp = I915_READ(upper_reg); \ + } while (upper != tmp); \ + (u64)upper << 32 | lower; }) #define POSTING_READ(reg) (void)I915_READ_NOTRACE(reg) #define POSTING_READ16(reg) (void)I915_READ16_NOTRACE(reg) |