From: Ben Grisdale <[email protected]>
mtk_dsi_host_transfer() decides where the payload starts in the
received data based on the byte count returned by mtk_dsi_recv_cnt(),
treating anything longer than 2 bytes as a long packet.
This breaks long read responses with a 1 or 2 byte payload: they are
treated as short packets, so the word count from the packet header is
copied into rx_buf instead of the payload.
Fix this by checking the packet's data type instead of inferring it
from the length.
Fixes: 21898816831f ("drm/mediatek: add dsi transfer function")
Cc: [email protected]
Signed-off-by: Ben Grisdale <[email protected]>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
b/drivers/gpu/drm/mediatek/mtk_dsi.c
index f82506e10fd5..de4414b51abb 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -165,6 +165,10 @@
(type == MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM) || \
(type == MIPI_DSI_DCS_READ))
+#define MTK_DSI_IS_LONG_RESP(type) \
+ (((type) == MIPI_DSI_RX_GENERIC_LONG_READ_RESPONSE) || \
+ ((type) == MIPI_DSI_RX_DCS_LONG_READ_RESPONSE))
+
struct mtk_phy_timing {
u32 lpx;
u32 da_hs_prepare;
@@ -1171,7 +1175,7 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host
*host,
recv_cnt = mtk_dsi_recv_cnt(read_data[0], read_data);
- if (recv_cnt > 2)
+ if (MTK_DSI_IS_LONG_RESP(read_data[0]))
src_addr = &read_data[4];
else
src_addr = &read_data[1];
---
base-commit: 2efb7a11f1aa4d2dc285fe2680cca22cb9f72f64
change-id: 20261019-mtk-dsi-long-read-45bc8e49d08b
Best regards,
--
Ben Grisdale <[email protected]>
