Re: [PATCH v4 3/6] media: i2c: ov5693: Gate the MIPI clock lane for non-continuous clock

[Jakob Berg Jespersen]

Hi, just did a new test, see below


On Monday, August 31st, 2026 at 20:19, Fernando Rimoli <fernandorimoli11@xxxxxxxxx> wrote:
...
> Parse the "clock-noncontinuous" endpoint property (which sets the
> V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK flag) and, when it is present, gate
> the clock lane while idle at stream on. 
...

Tested-by: Jakob Berg Jespersen <dev@xxxxxxx> # Surface Pro 7+, IPU6 Tiger Lake

Retested on the Surface Pro 7+ now that both the value and the mechanism
have changed. This covers patches 3 to 6, so it exercises the bridge
matching on Tiger Lake rather than only the register value. Patches 1 and
2 are not exercised here: this machine enumerates the sensor as INT33BE.

Both kernels are v7.3-rc1, your base-commit, differing only by this
series. Front camera, 20 cold opens each, libcamera 0.7.1, full
resolution (sensor 2592x1944 BGGR-10):

  v7.3-rc1 unpatched       3/20 runs delivered frames; the other 17 ended
                           in "stream stop time out" with zero frames
  v7.3-rc1 + this series   20/20 runs at 28.64-28.65 fps, and one run of
                           600 frames with no drops

Reading MIPI_CTRL00 back over I2C during a live capture, on both kernels:

  unpatched    0x4800 = 0x00
  patched      0x4800 = 0x20

with 0x300a/0x300b reading 0x56/0x90 as a control that the bus and address
are right. So the bridge did supply clock-noncontinuous, the driver did act
on it, and the read-modify-write set bit 5 and nothing else.

Two things that may be worth having:

The unpatched register really is 0x00 on this machine, so your argument
that the whole-register write and the read-modify-write resolve to the
same value holds on Tiger Lake as well as on the Pro 9.

Zann580 asked on GitHub, when posting the 0x20 row, that the minimal 
value be confirmed from a built module before the patch was narrowed 
on the strength of a userspace poke. I think this does that.

(Surface Pro 7+, Fedora 44; kernel 7.3.0-rc1 versus 7.3.0-rc1 plus this
series; Tiger Lake IPU6 8086:9a19; ov5693 as INT33BE; libcamera 0.7.1.)

Regards,
Jakob