[PATCH 3/6] drm/radeon: add some HDMI comments

[Rafał Miłecki]

Signed-off-by: Rafał Miłecki <zajec5 at gmail.com>
---
 drivers/gpu/drm/radeon/evergreen_hdmi.c |   14 ++++++++++++++
 drivers/gpu/drm/radeon/radeon_display.c |    5 +++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/radeon/evergreen_hdmi.c b/drivers/gpu/drm/radeon/evergreen_hdmi.c
index 4fdecc2..8b64bf1 100644
--- a/drivers/gpu/drm/radeon/evergreen_hdmi.c
+++ b/drivers/gpu/drm/radeon/evergreen_hdmi.c
@@ -143,6 +143,13 @@ void evergreen_hdmi_setmode(struct drm_encoder *encoder, struct drm_display_mode
 
 	WREG32(HDMI_GC + offset, 0); /* unset HDMI_GC_AVMUTE */
 
+	/*
+	 * At this point fglrx reads following regs:
+	 * DCE41: 0x49c
+	 * DCE5: 0x480 0x484 0x488
+	 * Is that something audio related?
+	 */
+
 	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
 	if (err < 0) {
 		DRM_ERROR("failed to setup AVI infoframe: %zd\n", err);
@@ -158,6 +165,13 @@ void evergreen_hdmi_setmode(struct drm_encoder *encoder, struct drm_display_mode
 	evergreen_hdmi_update_avi_infoframe(encoder, buffer, sizeof(buffer));
 	evergreen_hdmi_update_ACR(encoder, mode->clock);
 
+	/*
+	 * At this point fglrx changes following regs:
+	 * DCE41: 0x7a70
+	 * DCE5: 0x7a70 and 0x64ec
+	 * Is that something audio related?
+	 */
+
 	/* it's unknown what these bits do excatly, but it's indeed quite useful for debugging */
 	WREG32(AFMT_RAMP_CONTROL0 + offset, 0x00FFFFFF);
 	WREG32(AFMT_RAMP_CONTROL1 + offset, 0x007FFFFF);
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index e38fd55..a83c272 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -1261,6 +1261,11 @@ static void radeon_afmt_init(struct radeon_device *rdev)
 			rdev->mode_info.afmt[1]->offset = EVERGREEN_CRTC1_REGISTER_OFFSET;
 			rdev->mode_info.afmt[1]->id = 1;
 		}
+		/*
+		 * According to the commens above we should use !DCE41 || DCE5,
+		 * condition, however there isn't any DCE5 that is DCE41, so
+		 * DCE5 check is not needed.
+		 */
 		if (!ASIC_IS_DCE41(rdev)) {
 			rdev->mode_info.afmt[2] = kzalloc(sizeof(struct radeon_afmt), GFP_KERNEL);
 			if (rdev->mode_info.afmt[2]) {
-- 
1.7.10.4