Re: [PATCH 2/2] [media] ds3000: properly report firmware loading issues

["Rémi Cardona" <remi.cardona@smartjog.com>]

Hi Antti,

On 08/30/2012 03:39 PM, Antti Palosaari wrote:
> As I understand firmware downloading failure is coming from the fact
> that register read fails => fails to detect if firmware is already
> running or not.

Well we actually see 2 cases:

 - the register read failure (when ds3000_readreg() returns negative
values). This case is fairly rare, and no changes we've done to the
driver allowed us to make those cards work.

 - the register read returning 0. Looking at the current code, it looks
like the 0xb2 register is supposed to mean that a firmware is loaded.
This case is fairly common: we've had many cards randomly saying that a
firmware was loaded when none had been. Often, a simple reboot will do
the trick. But sometimes, forcing the firmware upload (ie, bypassing the
0xb2 register check) allows the stubborn cards to function properly.

> Original behavior to expect firmware is loaded and running when register
> read fails is very stupid and your fix seems much better.

Well, this patch should not really change the behavior. It just
propagates register read errors to ds3000_initfe(). It'll just fail earlier.

> So first priority should be try fix that issue with register read. Is it
> coming from the USB stack (eg. error 110 timeout) or some other error
> coming from the fact chip answers wrong?

The cards we're using are PCIe (and not the ones with an embedded USB
controller).

> Do you see other register I/O failing too?

I'll see if I can get you an answer for that, since the cards are
shipped with the appliance we send to our customers. Remote debugging is
somewhat tricky.

> Does adding few usec sleep help?

I'm not quite sure where to add those sleeps. In the register
reading/writing functions? 10us? 100us?

Many thanks

Rémi