diff options
| author | Luben Tuikov <luben.tuikov@amd.com> | 2021-07-02 19:58:42 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2021-07-08 15:12:51 -0400 |
| commit | c0838d3a93fc5e51b4a9654f53f499da1778dad8 (patch) | |
| tree | c768cb17e118cf6651a08e19bd75e515e83acd77 /drivers/gpu/drm/amd/pm/swsmu/smu13 | |
| parent | ae87df077554347e89d39a7383e74547401c7f5d (diff) | |
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>
Diffstat (limited to 'drivers/gpu/drm/amd/pm/swsmu/smu13')
| -rw-r--r-- | drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c index c1c7aefa9d8f..c16ca0c78e93 100644 --- a/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c +++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c @@ -1510,7 +1510,7 @@ static const struct i2c_algorithm aldebaran_i2c_algo = { }; static const struct i2c_adapter_quirks aldebaran_i2c_control_quirks = { - .flags = I2C_AQ_COMB | I2C_AQ_COMB_SAME_ADDR, + .flags = I2C_AQ_COMB | I2C_AQ_COMB_SAME_ADDR | I2C_AQ_NO_ZERO_LEN, .max_read_len = MAX_SW_I2C_COMMANDS, .max_write_len = MAX_SW_I2C_COMMANDS, .max_comb_1st_msg_len = 2, |