[PATCH v2 0/2] platform/x86: dell-uart-backlight: recover from stray EC response byte

From: chitranshmandhaniya

Date: Thu Oct 15 2026 - 03:47:35 EST


From: Chitransh Mandhaniya <Chitransh_Mandhaniya@xxxxxxxx>

On some Dell AIO machines the EC occasionally inserts a spurious byte
after the cmd-echo in UART backlight response frames, causing checksum
mismatches and -EIO.

Patch 1 extracts the response parsing into a dell_uart_bl_receive_data()
helper so it can be called again after resyncing.

Patch 2 adds the stray byte recovery: on checksum mismatch, drop the
byte at the first payload position, shift data down, and call the helper
again to re-fetch the checksum byte from the wire.

v1 -> v2:
- Extract dell_uart_bl_receive_data() helper instead of using a
for-loop with pass counter, call it again after resync (Ilpo)
- Split into two patches: refactor + feature (Ilpo)

Chitransh Mandhaniya (2):
platform/x86: dell-uart-backlight: extract dell_uart_bl_receive_data()
helper
platform/x86: dell-uart-backlight: recover from stray EC response byte

.../platform/x86/dell/dell-uart-backlight.c | 63 ++++++++++++++-----
1 file changed, 48 insertions(+), 15 deletions(-)

--
2.43.0