On 19/02/2020 00:03, Chris Wilson wrote:
Quoting Lionel Landwerlin (2020-02-18 21:54:03)
On 16/02/2020 18:17, Chris Wilson wrote:
Since we use a HW readback or estimation of the CS timestamp frequency,
sometimes it may result in 0. Avoid the division-by-zero in computing
its reciprocal, the timestamp period.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_device_info.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
index a97437fac884..18d9de488593 100644
--- a/drivers/gpu/drm/i915/intel_device_info.c
+++ b/drivers/gpu/drm/i915/intel_device_info.c
@@ -1044,13 +1044,17 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
}
/* Initialize command stream timestamp frequency */
- runtime->cs_timestamp_frequency_khz = read_timestamp_frequency(dev_priv);
- runtime->cs_timestamp_period_ns =
- div_u64(1e6, runtime->cs_timestamp_frequency_khz);
- drm_dbg(&dev_priv->drm,
- "CS timestamp wraparound in %lldms\n",
- div_u64(mul_u32_u32(runtime->cs_timestamp_period_ns, S32_MAX),
- USEC_PER_SEC));
+ runtime->cs_timestamp_frequency_khz =
+ read_timestamp_frequency(dev_priv);
+ if (runtime->cs_timestamp_frequency_khz) {
+ runtime->cs_timestamp_period_ns =
+ div_u64(1e6, runtime->cs_timestamp_frequency_khz);
+ drm_dbg(&dev_priv->drm,
+ "CS timestamp wraparound in %lldms\n",
+ div_u64(mul_u32_u32(runtime->cs_timestamp_period_ns,
+ S32_MAX),
+ USEC_PER_SEC));
+ }
Arg this is used in i915-perf in at least one place as denominator too...
This was a quick fix for BAT. See
https://patchwork.freedesktop.org/patch/353455/?series=73507&rev=1
then there are only a handful of platforms for which we don't know the
frequency, none of which matter for i915-perf.
-Chris
Ah, you got me worried :)
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
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