Hi,
On Thursday 13 March 2014 07:59 PM, Kamil Debski wrote:
Hi,
From: Archit Taneja [mailto:archit@xxxxxx]
Sent: Thursday, March 13, 2014 1:09 PM
Hi Kamil,
On Thursday 13 March 2014 05:18 PM, Kamil Debski wrote:
Hi Archit,
From: Archit Taneja [mailto:archit@xxxxxx]
Sent: Tuesday, March 11, 2014 9:34 AM
vpe fops(vpe_open in particular) should be called only when VPDMA
firmware is loaded. File operations on the video device are possible
the moment it is registered.
Currently, we register the video device for VPE at driver probe,
after calling a vpdma helper to initialize VPDMA and load firmware.
This function is non-blocking(it calls request_firmware_nowait()),
and doesn't ensure that the firmware is actually loaded when it
returns.
We remove the device registration from vpe probe, and move it to a
callback provided by the vpe driver to the vpdma library, through
vpdma_create().
The ready field in vpdma_data is no longer needed since we always
have firmware loaded before the device is registered.
A minor problem with this approach is that if the
video_register_device fails(which doesn't really happen), the vpe
platform device would be registered.
however, there won't be any v4l2 device corresponding to it.
Could you explain to me one thing. request_firmware cannot be used in
probe, thus you are using request_firmware_nowait. Why cannot the
firmware be loaded on open with a regular request_firmware that is
waiting?
I totally agree with you here. Placing the firmware in open() would
probably make more sense.
The reason I didn't place it in open() is because I didn't want to
release firmware in a corresponding close(), and be in a situation
where the firmware is loaded multiple times in the driver's lifetime.
Would it be possible to load firmware in open and release it in remove?
I know that this would disturb the symmetry between open-release and
probe-remove. But this could work.
That might work.
Currently, the driver doesn't do any clock management, it just enables
the clocks in probe, and disables them in remove. I need to check how
the firmware is dependent on clocks. We could make a better decision
about where to release the firmware with that information.
Archit
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