drm/radeon/kms: auto detect pcie link speed from root port
This check the root ports supported link speeds and enables
GEN2 mode if the 5.0 GT link speed is available.
The first 3.0 cards are SI so they will probably need more investigation.
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index eb4704e..ca8ffec 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -1112,6 +1112,8 @@
{
u32 link_width_cntl, lanes, speed_cntl, tmp;
u16 link_cntl2;
+ u32 mask;
+ int ret;
if (radeon_pcie_gen2 == 0)
return;
@@ -1126,6 +1128,15 @@
if (ASIC_IS_X2(rdev))
return;
+ ret = drm_pcie_get_speed_cap_mask(rdev->ddev, &mask);
+ if (ret != 0)
+ return;
+
+ if (!(mask & DRM_PCIE_SPEED_50))
+ return;
+
+ DRM_INFO("enabling PCIE gen 2 link speeds, disable with radeon.pcie_gen2=0\n");
+
/* advertise upconfig capability */
link_width_cntl = RREG32_PCIE_P(PCIE_LC_LINK_WIDTH_CNTL);
link_width_cntl &= ~LC_UPCONFIGURE_DIS;