From ce3b4ee2f7d315dadd56ba19587b58339e5d6185 Mon Sep 17 00:00:00 2001 From: Dom Cobley Date: Tue, 10 Nov 2020 20:04:08 +0000 Subject: [PATCH] vc4: Clear unused infoframe packet RAM registers 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 Signed-off-by: Dom Cobley --- drivers/gpu/drm/vc4/vc4_hdmi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -440,9 +440,11 @@ static void vc4_hdmi_write_infoframe(str 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; @@ -478,6 +480,13 @@ static void vc4_hdmi_write_infoframe(str 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));