Re: [PATCH 07/24] xc5000: properly report i2c write failures

[Devin Heitmueller <dheitmueller@kernellabs.com>]

> I can't load firmware like error of below link.
>
> https://bugs.launchpad.net/ubuntu/+source/linux-firmware-nonfree/+bug/1263837
>
> This error is related with this patch. This fix is right but above error is
> created after this fix
> because my device makes WatchDogTimer to 0 when load firmware.
> Maybe it will be related with XREG_BUSY register but i can't check it.
>
> I removed this fix, but i have faced at other error with "xc5000: PLL not
> running after fwload"
> So i have commented like below.
>
> static const struct xc5000_fw_cfg xc5000a_1_6_114 = {
>         .name = XC5000A_FIRMWARE,
>         .size = 12401,
>         //.pll_reg = 0x806c,
> };
>
> Then, xc5000 device works well.
>
> I don't have xc5000 datasheet so i can't debug xc5000 driver anymore.

Hi Joonyoung,

Assuming this is the DViCO FusionHDTV7 device that uses the
au0828/au8522, I suspect that what's happening here is your I2C
controller is not stable.  The I2C clock stretching done by the xc5000
often exposed bugs in various bridge drivers and the au0828 was no
exception.  I had to work around these hardware bugs in the au0828
driver but I made them specific to the HVR-950q since that was the
only device I could test with.

In other words, the xc5000 is most likely doing exactly what it is
supposed to, and the increased robustness of the tuner driver with
those two patches exposed intermittent I2C failures in au0828 that
were previously being silently discarded (resulting in indeterminate
behavior).

I would recommending looking at the changes in au0828-cards.c for the
HVR-950q and add the code necessary to make them also apply for the
DVICO device, and that should resolve your problems (in particular the
i2c_clk_divider field should be set).

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com