radeon/pm: Guard access to rdev->pm.power_state array

It's never allocated on systems without an ATOMBIOS or COMBIOS ROM.

Should fix an oops I encountered while resetting the GPU after a lockup
on my PowerBook with an RV350.

Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index c0ff200..0b24c4c 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -1010,8 +1010,10 @@ static void radeon_pm_resume_old(struct radeon_device *rdev)
        rdev->pm.current_clock_mode_index = 0;
        rdev->pm.current_sclk = rdev->pm.default_sclk;
        rdev->pm.current_mclk = rdev->pm.default_mclk;
-       rdev->pm.current_vddc = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.voltage;
-       rdev->pm.current_vddci = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.vddci;
+       if (rdev->pm.power_state) {
+               rdev->pm.current_vddc = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.voltage;
+               rdev->pm.current_vddci = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.vddci;
+       }
        if (rdev->pm.pm_method == PM_METHOD_DYNPM
            && rdev->pm.dynpm_state == DYNPM_STATE_SUSPENDED) {
                rdev->pm.dynpm_state = DYNPM_STATE_ACTIVE;