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linux/drivers/gpu/drm/amd
Luben Tuikov c0838d3a93 drm/amdgpu: The I2C IP doesn't support 0 writes/reads
The I2C IP doesn't support writes or reads of 0 bytes.

In order for a START/STOP transaction to take
place on the bus, the data written/read has to be
at least one byte.

That is, you cannot generate a write with 0 bytes,
just to get the ACK from a device, just so you can
probe that device if it is on the bus and so to
discover all devices on the bus--you'll have to
read at least one byte. Writes of 0 bytes generate
no START/STOP on this I2C IP--the bus is not
engaged at all.

Set the I2C_AQ_NO_ZERO_LEN to the existing I2C
quirk tables for Aldebaran, Arcturus, Navi10 and
Sienna Cichlid, and add a quirk table to the I2C
driver which drives the bus when the SMU
doesn't--for instance on Vega20.

Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Cc: Lijo Lazar <Lijo.Lazar@amd.com>
Cc: John Clements <john.clements@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Lijo Lazar <Lijo.Lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2021-07-08 15:12:51 -04:00
..
acp drm: amd/acp: fix broken menu structure 2020-03-13 11:52:35 -04:00
amdgpu drm/amdgpu: The I2C IP doesn't support 0 writes/reads 2021-07-08 15:12:51 -04:00
amdkfd drm/amdkfd: Maintain svm_bo reference in page->zone_device_data 2021-07-01 00:05:41 -04:00
display drm/amd/display: Extend DMUB diagnostic logging to DCN3.1 2021-07-01 00:05:40 -04:00
include drm/amdgpu: add license to umc_8_7_0_sh_mask.h 2021-07-01 00:25:33 -04:00
pm drm/amdgpu: The I2C IP doesn't support 0 writes/reads 2021-07-08 15:12:51 -04:00