i965: Use drm_intel_get_aperture_sizes instead of hard-coded 2GiB

Systems with little physical memory installed will report less than
2GiB, and some systems may (hypothetically?) have a larger address space
for the GPU.  My IVB still reports 1534.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Cc: "10.0" <[email protected]>
(cherry picked from commit cb6182bdfa7c8a5a773ec21112886f742df99840)

1 files changed, 7 insertions, 3 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index 6bcfe2c3115..10ebfb10b8e 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -824,10 +824,14 @@ brw_query_renderer_integer(__DRIscreen *psp, int param, int *value)
       /* Once a batch uses more than 75% of the maximum mappable size, we
        * assume that there's some fragmentation, and we start doing extra
        * flushing, etc.  That's the big cliff apps will care about.
-       *
-       * Can only map 2G onto the GPU through the GTT.
        */
-      const unsigned gpu_mappable_megabytes = 2 * 1024 * 3 / 4;
+      size_t aper_size;
+      size_t mappable_size;
+
+      drm_intel_get_aperture_sizes(psp->fd, &mappable_size, &aper_size);
+
+      const unsigned gpu_mappable_megabytes =
+         (aper_size / (1024 * 1024)) * 3 / 4;
 
       const long system_memory_pages = sysconf(_SC_PHYS_PAGES);
       const long system_page_size = sysconf(_SC_PAGE_SIZE);