[PATCH v2] drm/radeon: default to 2048 MB GART size on SI+

[Grigori Goronzy]

Newer ASICs have more VRAM on average and allocating more GART as
well can have advantages. Also see commit edcd26e8.

Ideally, we should scale GART size based on actual VRAM size, but
that requires significant restructuring of initialization.

v2: extract small helper, apply to error paths
---
Sorry, I forgot to amend these additional cleanup in the series. Please
ignore the other patch. -Grigori
 drivers/gpu/drm/radeon/radeon_device.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index a7fdfa4..14deeae 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1080,6 +1080,22 @@ static bool radeon_check_pot_argument(int arg)
 }
 
 /**
+ * Determine a sensible default GART size according to ASIC family.
+ *
+ * @family ASIC family name
+ */
+static int radeon_gart_size_auto(enum radeon_family family)
+{
+	/* default to a larger gart size on newer asics */
+	if (family >= CHIP_TAHITI)
+		return 2048;
+	else if (family >= CHIP_RV770)
+		return 1024;
+	else
+		return 512;
+}
+
+/**
  * radeon_check_arguments - validate module params
  *
  * @rdev: radeon_device pointer
@@ -1097,27 +1113,17 @@ static void radeon_check_arguments(struct radeon_device *rdev)
 	}
 
 	if (radeon_gart_size == -1) {
-		/* default to a larger gart size on newer asics */
-		if (rdev->family >= CHIP_RV770)
-			radeon_gart_size = 1024;
-		else
-			radeon_gart_size = 512;
+		radeon_gart_size = radeon_gart_size_auto(rdev->family);
 	}
 	/* gtt size must be power of two and greater or equal to 32M */
 	if (radeon_gart_size < 32) {
 		dev_warn(rdev->dev, "gart size (%d) too small\n",
 				radeon_gart_size);
-		if (rdev->family >= CHIP_RV770)
-			radeon_gart_size = 1024;
-		else
-			radeon_gart_size = 512;
+		radeon_gart_size = radeon_gart_size_auto(rdev->family);
 	} else if (!radeon_check_pot_argument(radeon_gart_size)) {
 		dev_warn(rdev->dev, "gart size (%d) must be a power of 2\n",
 				radeon_gart_size);
-		if (rdev->family >= CHIP_RV770)
-			radeon_gart_size = 1024;
-		else
-			radeon_gart_size = 512;
+		radeon_gart_size = radeon_gart_size_auto(rdev->family);
 	}
 	rdev->mc.gtt_size = (uint64_t)radeon_gart_size << 20;
 
-- 
1.9.1