diff options
| author | Dave Airlie <airlied@redhat.com> | 2025-03-03 18:56:03 +0300 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2025-05-19 00:14:45 +0300 |
| commit | f0ddbb1eed1898286d2bd99fd6ab64ca9700d267 (patch) | |
| tree | 40e8e1ebe79cd79c9d1e267d737ad810bac98266 /drivers/gpu/drm | |
| parent | 284ad706ad2f50974d66dd1a22e985a5a4d329de (diff) | |
| download | linux-f0ddbb1eed1898286d2bd99fd6ab64ca9700d267.tar.xz | |
drm/dp: add option to disable zero sized address only transactions.
Some older NVIDIA and some newer NVIDIA hardware/firmware seems to
have issues with address only transactions (firmware rejects them).
Add an option to the core drm dp to avoid address only transactions,
This just puts the MOT flag removal on the last message of the transfer
and avoids the start of transfer transaction.
This with the flag set in nouveau, allows eDP probing on GB203 device.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@nvidia.com>
Reviewed-by: Timur Tabi <ttabi@nvidia.com>
Tested-by: Timur Tabi <ttabi@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_helper.c | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index 56c7e3318f01..f2a6559a2710 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -2137,14 +2137,17 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, for (i = 0; i < num; i++) { msg.address = msgs[i].addr; - drm_dp_i2c_msg_set_request(&msg, &msgs[i]); - /* Send a bare address packet to start the transaction. - * Zero sized messages specify an address only (bare - * address) transaction. - */ - msg.buffer = NULL; - msg.size = 0; - err = drm_dp_i2c_do_msg(aux, &msg); + + if (!aux->no_zero_sized) { + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); + /* Send a bare address packet to start the transaction. + * Zero sized messages specify an address only (bare + * address) transaction. + */ + msg.buffer = NULL; + msg.size = 0; + err = drm_dp_i2c_do_msg(aux, &msg); + } /* * Reset msg.request in case in case it got @@ -2163,6 +2166,8 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, msg.buffer = msgs[i].buf + j; msg.size = min(transfer_size, msgs[i].len - j); + if (j + msg.size == msgs[i].len && aux->no_zero_sized) + msg.request &= ~DP_AUX_I2C_MOT; err = drm_dp_i2c_drain_msg(aux, &msg); /* @@ -2180,15 +2185,17 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, } if (err >= 0) err = num; - /* Send a bare address packet to close out the transaction. - * Zero sized messages specify an address only (bare - * address) transaction. - */ - msg.request &= ~DP_AUX_I2C_MOT; - msg.buffer = NULL; - msg.size = 0; - (void)drm_dp_i2c_do_msg(aux, &msg); + if (!aux->no_zero_sized) { + /* Send a bare address packet to close out the transaction. + * Zero sized messages specify an address only (bare + * address) transaction. + */ + msg.request &= ~DP_AUX_I2C_MOT; + msg.buffer = NULL; + msg.size = 0; + (void)drm_dp_i2c_do_msg(aux, &msg); + } return err; } |