On 2018-11-06 12:52, Fabrizio Castro wrote: > While adding SiI9022A support to the iwg23s board, it came > up that when the HDMI transmitter is in pass through mode the > device is not compliant with the I2C specification anymore, > as it requires a far bigger tbuf, due to a delay the HDMI > transmitter is adding when relaying the STOP condition on the > monitor i2c side of things. > > When not providing an appropriate delay after the STOP condition > the i2c bus would get stuck. Also, any other traffic on the bus > while talking to the monitor may cause the transaction to fail > or even cause issues with the i2c bus as well. > > I2c-gates seemed to reach consent as a possible way to address > these issues, and as such this patch is implementing a solution > based on that. Since others are clearly relying on the current > implementation of the driver, this patch won't require any DT > changes. > > Since we don't want any interference during the DDC Bus > Request/Grant procedure and while talking to the monitor, we > have to use the adapter locking primitives rather than the > i2c-mux locking primitives. > > Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx> Reviewed-by: Peter Rosin <peda@xxxxxxxxxx> Cheers, Peter > > --- > v2->v3: > * Incorporated comments from Boris Brezillon and Peter Rosin > > v1->v2: > * Incorporated comments from Peter Rosin > > drivers/gpu/drm/bridge/sii902x.c | 247 ++++++++++++++++++++++++++++----------- > 1 file changed, 178 insertions(+), 69 deletions(-)
