drm/radeon/kms/igp: fix possible divide by 0 in bandwidth code (v2)

Some IGP systems specify the system memory clock in the Firmware
table rather than the IGP info table.  Check both and make sure
we have a value system memory clock value.

v2: make sure rs690_pm_info is called on rs780/rs880 as well.

fixes a regression since 07d4190327b02ab3aaad25a2d168f79d92e8f8c2.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index b32064dad95d..90f28175a7bc 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -1219,8 +1219,10 @@ int r600_mc_init(struct radeon_device *rdev)
         rdev->mc.visible_vram_size = rdev->mc.aper_size;
         r600_vram_gtt_location(rdev, &rdev->mc);
 
-        if (rdev->flags & RADEON_IS_IGP)
+        if (rdev->flags & RADEON_IS_IGP) {
+                rs690_pm_info(rdev);
                 rdev->mc.igp_sideport_enabled = radeon_atombios_sideport_present(rdev);
+        }
         radeon_update_bandwidth_info(rdev);
         return 0;
 }