i965: Query and store GPU properties from kernel

Certain products are not uniquely identifiable based on device id alone. The
kernel exports an interface to help deal with this. This patch merely introduces
the consumer of the interface and makes sure nothing breaks.

It is also possible to use these values for programming GPGPU mode, and I plan
to do that as well.

The interface was introduced in libdrm 2.4.60, which is already required, so it
should all be fine.

v2: Some minor changes recommended by Matt

Signed-off-by: Ben Widawsky <[email protected]>
Reviewed-by: Jordan Justen <[email protected]>

2 files changed, 31 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index ee7c1d7bc2c..64b8524c64b 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -1082,6 +1082,7 @@ static bool
 intel_init_bufmgr(struct intel_screen *intelScreen)
 {
    __DRIscreen *spriv = intelScreen->driScrnPriv;
+   bool devid_override = getenv("INTEL_DEVID_OVERRIDE") != NULL;
 
    intelScreen->no_hw = getenv("INTEL_NO_HW") != NULL;
 
@@ -1099,6 +1100,25 @@ intel_init_bufmgr(struct intel_screen *intelScreen)
       return false;
    }
 
+   intelScreen->subslice_total = -1;
+   intelScreen->eu_total = -1;
+
+   /* Everything below this is for real hardware only */
+   if (intelScreen->no_hw || devid_override)
+      return true;
+
+   intel_get_param(spriv, I915_PARAM_SUBSLICE_TOTAL,
+                   &intelScreen->subslice_total);
+   intel_get_param(spriv, I915_PARAM_EU_TOTAL, &intelScreen->eu_total);
+
+   /* Without this information, we cannot get the right Braswell brandstrings,
+    * and we have to use conservative numbers for GPGPU on many platforms, but
+    * otherwise, things will just work.
+    */
+   if (intelScreen->subslice_total == -1 || intelScreen->eu_total == -1)
+      _mesa_warning(NULL,
+                    "Kernel 4.1 required to properly query GPU properties.\n");
+
    return true;
 }
 
diff --git a/src/mesa/drivers/dri/i965/intel_screen.h b/src/mesa/drivers/dri/i965/intel_screen.h
index 3a5f22c3a67..01d45d0c016 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.h
+++ b/src/mesa/drivers/dri/i965/intel_screen.h
@@ -81,7 +81,17 @@ struct intel_screen
     * I915_PARAM_CMD_PARSER_VERSION parameter
     */
    int cmd_parser_version;
- };
+
+   /**
+    * Number of subslices reported by the I915_PARAM_SUBSLICE_TOTAL parameter
+    */
+   int subslice_total;
+
+   /**
+    * Number of EUs reported by the I915_PARAM_EU_TOTAL parameter
+    */
+   int eu_total;
+};
 
 extern void intelDestroyContext(__DRIcontext * driContextPriv);