This is a note to let you know that I've just added the patch titled
drm/mipi-dbi: align max_chunk to 2 in spi_transfer
to the 5.10-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-mipi-dbi-align-max_chunk-to-2-in-spi_transfer.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b135a42205f361977f19a833132f08a147411766
Author: Yunhao Tian <t123yh.xyz@xxxxxxxxx>
Date: Tue May 10 11:02:19 2022 +0800
drm/mipi-dbi: align max_chunk to 2 in spi_transfer
[ Upstream commit 435c249008cba04ed6a7975e9411f3b934620204 ]
In __spi_validate, there's a validation that no partial transfers
are accepted (xfer->len % w_size must be zero). When
max_chunk is not a multiple of bpw (e.g. max_chunk = 65535,
bpw = 16), the transfer will be rejected.
This patch aligns max_chunk to 2 bytes (the maximum value of bpw is 16),
so that no partial transfer will occur.
Fixes: d23d4d4dac01 ("drm/tinydrm: Move tinydrm_spi_transfer()")
Signed-off-by: Yunhao Tian <t123yh.xyz@xxxxxxxxx>
Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510030219.2486687-1-t123yh.xyz@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index 230c4fd7131c..9f132229aed1 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -1137,6 +1137,13 @@ int mipi_dbi_spi_transfer(struct spi_device *spi, u32 speed_hz,
size_t chunk;
int ret;
+ /* In __spi_validate, there's a validation that no partial transfers
+ * are accepted (xfer->len % w_size must be zero).
+ * Here we align max_chunk to multiple of 2 (16bits),
+ * to prevent transfers from being rejected.
+ */
+ max_chunk = ALIGN_DOWN(max_chunk, 2);
+
spi_message_init_with_transfers(&m, &tr, 1);
while (len) {
