[Mesa-dev] [PATCH 3/3] anv: query CS timestamp frequency from the kernel

[Lionel Landwerlin]

The reference value in gen_device_info isn't going to be acurate on
Gen10+. We should query it from the kernel, which reads a couple of
register to compute the actual value.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
 src/intel/vulkan/anv_device.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
index b5577ee61de..ac2dc9bf131 100644
--- a/src/intel/vulkan/anv_device.c
+++ b/src/intel/vulkan/anv_device.c
@@ -370,6 +370,19 @@ anv_physical_device_init(struct anv_physical_device *device,
 
    bool swizzled = anv_gem_get_bit6_swizzle(fd, I915_TILING_X);
 
+   /* Starting with Gen10, the timestamp frequency of the command streamer may
+    * vary from one part to another. We can query the value from the kernel.
+    */
+   if (device->info.gen >= 10) {
+      int timestamp_frequency =
+         anv_gem_get_param(fd, I915_PARAM_CS_TIMESTAMP_FREQUENCY);
+
+      if (timestamp_frequency < 0)
+         intel_logw("Kernel 4.16-rc1+ required to properly query CS timestamp frequency");
+      else
+         device->info.timestamp_frequency = timestamp_frequency;
+   }
+
    /* GENs prior to 8 do not support EU/Subslice info */
    if (device->info.gen >= 8) {
       device->subslice_total = anv_gem_get_param(fd, I915_PARAM_SUBSLICE_TOTAL);
-- 
2.15.1