Den 10.05.2022 05.02, skrev Yunhao Tian:

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@gmail.com

Thanks, applied to drm-misc-next.

Noralf.

drivers/gpu/drm/drm_mipi_dbi.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c index 71b646c4131f..00d470ff071d 100644 --- a/drivers/gpu/drm/drm_mipi_dbi.c +++ b/drivers/gpu/drm/drm_mipi_dbi.c @@ -1183,6 +1183,13 @@ 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) {