Am 09.08.2013 16:13, schrieb Alan Stern:
On Fri, 9 Aug 2013, Christian Lamparter wrote:
After loading firmware, a reset generally is necessary. Some devices
will do it themselves; others require you to call usb_reset_device().
This makes things complicated. Because, as far as I remember,
usb_reset_device() will cause the current driver to be unbound
unless its called during .probe, right?
If the driver defines pre_reset and post_reset methods, it won't get
unbound during a reset.
You see, ath9k_htc loads its firmware asynchronously in ".probe"
(ath9k_htc's .probe routine finishes before the firmware is
retrieved via the firmware loader helper... so part of the
firmware download is done in a firmware_complete callback
on a workqueue).
So, if we call usb_reset_device there and the driver is unbound
and later rebound. the next ath9k_htc .probe will start again and
again and again not knowing that it is already initialized
(and we have a loop).
This could be solved, if the devices changes the usb-id again
when a proper "wifi" ath9k_htc firmware was downloaded. So, the
driver would know that it doesn't have to download and reset
the device... But we need a "free" USB-ID for that.
What about a "get firmware version" sort of thing? There really should
be a way for the driver to tell whether the firmware has already been
updated.
I was not able to find good direct way to check firmware version. If i
would add some new command then i will get option like: if responding FW
is updated; if not, then dead or old.
How about overwriting iProduct field? Let say, if iProduct == ath9k_htc,
then firmware is updated? Is it more or less acceptable method? I need
to ask this because it is really new for me.
--
Regards,
Oleksij
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