drm/radeon/kms/atom: fix potential oops in spread spectrum code

Make sure we have an LVDS encoder before casting enc_priv.

[airlied: also fix two missing cpu_to_le16 casts we noticed on irc]

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

1 files changed, 12 insertions, 9 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 8516e1b2329a..c15287a590ff 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -368,14 +368,17 @@ static void atombios_set_ss(struct drm_crtc *crtc, int enable)
         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
                 if (encoder->crtc == crtc) {
                         radeon_encoder = to_radeon_encoder(encoder);
-                        dig = radeon_encoder->enc_priv;
                         /* only enable spread spectrum on LVDS */
-                        if (dig && dig->ss) {
-                                percentage = dig->ss->percentage;
-                                type = dig->ss->type;
-                                step = dig->ss->step;
-                                delay = dig->ss->delay;
-                                range = dig->ss->range;
+                        if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
+                                dig = radeon_encoder->enc_priv;
+                                if (dig && dig->ss) {
+                                        percentage = dig->ss->percentage;
+                                        type = dig->ss->type;
+                                        step = dig->ss->step;
+                                        delay = dig->ss->delay;
+                                        range = dig->ss->range;
+                                } else if (enable)
+                                        return;
                         } else if (enable)
                                 return;
                         break;
@@ -387,7 +390,7 @@ static void atombios_set_ss(struct drm_crtc *crtc, int enable)
 
         if (ASIC_IS_AVIVO(rdev)) {
                 memset(&args, 0, sizeof(args));
-                args.usSpreadSpectrumPercentage = percentage;
+                args.usSpreadSpectrumPercentage = cpu_to_le16(percentage);
                 args.ucSpreadSpectrumType = type;
                 args.ucSpreadSpectrumStep = step;
                 args.ucSpreadSpectrumDelay = delay;
@@ -397,7 +400,7 @@ static void atombios_set_ss(struct drm_crtc *crtc, int enable)
                 atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
         } else {
                 memset(&legacy_args, 0, sizeof(legacy_args));
-                legacy_args.usSpreadSpectrumPercentage = percentage;
+                legacy_args.usSpreadSpectrumPercentage = cpu_to_le16(percentage);
                 legacy_args.ucSpreadSpectrumType = type;
                 legacy_args.ucSpreadSpectrumStepSize_Delay = (step & 3) << 2;
                 legacy_args.ucSpreadSpectrumStepSize_Delay |= (delay & 7) << 4;