drm/radeon/kms: add module option for pcie gen2

Switching to pcie gen2 causes problems on some
boards.  Add a module option to turn it on/off.

There are gen2 compatability issues with some
motherboards it seems.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=33027

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 3a264aa3a79a..bd9ee90421e4 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -1372,6 +1372,9 @@ static void rv770_pcie_gen2_enable(struct radeon_device *rdev)
         u32 link_width_cntl, lanes, speed_cntl, tmp;
         u16 link_cntl2;
 
+        if (radeon_pcie_gen2 == 0)
+                return;
+
         if (rdev->flags & RADEON_IS_IGP)
                 return;