On Thu, 2017-02-16 at 22:57 +0000, Russell King - ARM Linux wrote: > On Thu, Feb 16, 2017 at 02:27:41PM -0800, Steve Longerbeam wrote: > > > > > > On 02/16/2017 02:20 PM, Russell King - ARM Linux wrote: > > >On Wed, Feb 15, 2017 at 06:19:02PM -0800, Steve Longerbeam wrote: > > >>In version 4: > > > > > >With this version, I get: > > > > > >[28762.892053] imx6-mipi-csi2: LP-11 timeout, phy_state = 0x00000000 > > >[28762.899409] ipu1_csi0: pipeline_set_stream failed with -110 > > > > > > > Right, in the imx219, on exit from s_power(), the clock and data lanes > > must be placed in the LP-11 state. This has been done in the ov5640 and > > tc358743 subdevs. > > The only way to do that is to enable streaming from the sensor, wait > an initialisation time, and then disable streaming, and wait for the > current line to finish. There is _no_ other way to get the sensor to > place its clock and data lines into LP-11 state. I thought going through LP-11 is part of the D-PHY transmitter initialization, during the LP->HS wakeup sequence. But then I have no access to MIPI specs. It is unfortunate that the i.MX6 MIPI CSI-2 core needs software assistance here, but could it be possible to trigger that sequence in the sensor and then without waiting switching to polling for LP-11 state in the i.MX6 MIPI CSI-2 receiver? > For that to happen, we need to program the sensor a bit more than we > currently do at power on (to a minimal resolution, and setting up the > PLLs), and introduce another 4ms on top of the 8ms or so that the > runtime resume function already takes. > > Looking at the SMIA driver, things are worse, and I suspect that it also > will not work with the current setup - the SMIA spec shows that the CSI > clock and data lines are tristated while the sensor is not streaming, > which means they aren't held at a guaranteed LP-11 state, even if that > driver momentarily enabled streaming. Hence, Freescale's (or is it > Synopsis') requirement may actually be difficult to satisfy. > > However, I regard runtime PM broken with the current imx-capture setup. > At the moment, power is controlled at the sensor by whether the media > links are enabled. So, if you have an enabled link coming off the > sensor, the sensor will be powered up, whether you're using it or not. > > Given that the number of applications out there that know about the > media subdevs is really quite small, this combination makes having > runtime PM in sensor devices completely pointless - they can't sleep > as long as they have an enabled link, which could be persistent over > many days or weeks. regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
