i965: Document inconsistent units the URB size is represented in.

Every other gen the representation of the URB size was changed and
previous ones weren't updated.  I'd be willing to write a series
normalizing this to be KB on all generations if anybody else cares.

2 files changed, 12 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 51d573a9435..a8455413e36 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -1026,7 +1026,13 @@ struct brw_context
       GLuint clip_start;
       GLuint sf_start;
       GLuint cs_start;
-      GLuint size; /* Hardware URB size, in KB. */
+      /**
+       * URB size in the current configuration.  The units this is expressed
+       * in are somewhat inconsistent, see brw_device_info::urb::size.
+       *
+       * FINISHME: Represent the URB size consistently in KB on all platforms.
+       */
+      GLuint size;
 
       /* True if the most recently sent _3DSTATE_URB message allocated
        * URB space for the GS.
diff --git a/src/mesa/drivers/dri/i965/brw_device_info.h b/src/mesa/drivers/dri/i965/brw_device_info.h
index 4a8fc537d43..73d682083a1 100644
--- a/src/mesa/drivers/dri/i965/brw_device_info.h
+++ b/src/mesa/drivers/dri/i965/brw_device_info.h
@@ -81,6 +81,11 @@ struct brw_device_info
    unsigned max_cs_threads;
 
    struct {
+      /**
+       * Hardware default URB size.  The units this is expressed in are
+       * somewhat inconsistent: 512b units on Gen4-5, KB on Gen6-7, and KB
+       * times the slice count on Gen8+.
+       */
       unsigned size;
       unsigned min_vs_entries;
       unsigned max_vs_entries;