This is a note to let you know that I've just added the patch titled
drm/vc4: hdmi: Clear unused infoframe packet RAM registers
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-vc4-hdmi-clear-unused-infoframe-packet-ram-regis.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 197dfd51be8a0640b2fd7ee7677a9672f4940ba1
Author: Dom Cobley <popcornmix@xxxxxxxxx>
Date: Mon Jun 13 16:47:46 2022 +0200
drm/vc4: hdmi: Clear unused infoframe packet RAM registers
[ Upstream commit b6079d1578dc4b4b8050d613a5449a63def7d1dd ]
Using a hdmi analyser the bytes in packet ram
registers beyond the length were visible in the
infoframes and it flagged the checksum as invalid.
Zeroing unused words of packet RAM avoids this
Fixes: 21317b3fba54 ("drm/vc4: Set up the AVI and SPD infoframes.")
Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220613144800.326124-20-maxime@xxxxxxxxxx
Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index e314e0a4c4c3..ecd49214bd92 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -461,9 +461,11 @@ static void vc4_hdmi_write_infoframe(struct drm_encoder *encoder,
const struct vc4_hdmi_register *ram_packet_start =
&vc4_hdmi->variant->registers[HDMI_RAM_PACKET_START];
u32 packet_reg = ram_packet_start->offset + VC4_HDMI_PACKET_STRIDE * packet_id;
+ u32 packet_reg_next = ram_packet_start->offset +
+ VC4_HDMI_PACKET_STRIDE * (packet_id + 1);
void __iomem *base = __vc4_hdmi_get_field_base(vc4_hdmi,
ram_packet_start->reg);
- uint8_t buffer[VC4_HDMI_PACKET_STRIDE];
+ uint8_t buffer[VC4_HDMI_PACKET_STRIDE] = {};
unsigned long flags;
ssize_t len, i;
int ret;
@@ -499,6 +501,13 @@ static void vc4_hdmi_write_infoframe(struct drm_encoder *encoder,
packet_reg += 4;
}
+ /*
+ * clear remainder of packet ram as it's included in the
+ * infoframe and triggers a checksum error on hdmi analyser
+ */
+ for (; packet_reg < packet_reg_next; packet_reg += 4)
+ writel(0, base + packet_reg);
+
HDMI_WRITE(HDMI_RAM_PACKET_CONFIG,
HDMI_READ(HDMI_RAM_PACKET_CONFIG) | BIT(packet_id));
