Re: [PATCH v3] media: imx: mipi csi-2: Don't fail if initial state times-out

[Sakari Ailus <sakari.ailus@iki.fi>]

On Tue, Jul 30, 2019 at 05:14:24AM -0300, Ezequiel Garcia wrote:
> Hey Hans,
> 
> On Mon, 2019-07-01 at 08:48 +0200, Philipp Zabel wrote:
> > On Thu, 2019-06-27 at 19:29 -0300, Fabio Estevam wrote:
> > > From: Ezequiel Garcia <ezequiel@collabora.com>
> > > 
> > > Not all sensors will be able to guarantee a proper initial state.
> > > This may be either because the driver is not properly written,
> > > or (probably unlikely) because the hardware won't support it.
> > > 
> > > While the right solution in the former case is to fix the sensor
> > > driver, the real world not always allows right solutions, due to lack
> > > of available documentation and support on these sensors.
> > > 
> > > Let's relax this requirement, and allow the driver to support stream start,
> > > even if the sensor initial sequence wasn't the expected.
> > > 
> > > Also improve the warning message to better explain the problem and provide
> > > a hint that the sensor driver needs to be fixed.
> > > 
> > > Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> > > Signed-off-by: Fabio Estevam <festevam@gmail.com>
> > 
> > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
> > 
> 
> This seems ready to pick and it has Philipp's and Steve's RB.

Hi Ezequiel,

In general the LP-11 condition should be detected by hardware (or firmware)
in such a way that it's detected even if a transmitter that holds the state
just a short period of time. In other words, software is not supposed to be
even testing for it.

Have you checked how it works if you simply leave out this test?

I remember that there has been hardware that does indeed require further
initialisation done only *after* LP-11 has been detected by _software_.

-- 
Regards,

Sakari Ailus