From: Dom Cobley popcornmix@gmail.com
[ 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@gmail.com Link: https://lore.kernel.org/r/20220613144800.326124-20-maxime@cerno.tech Signed-off-by: Maxime Ripard maxime@cerno.tech Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vc4/vc4_hdmi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 2ff53482d5d1..0fe04b1f9782 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -439,9 +439,11 @@ 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; @@ -477,6 +479,13 @@ 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));