call trace on Khadas VIM Pro with AP6255 WiFi

Heiner Kallweit hkallweit1 at
Sun Jun 4 13:41:18 PDT 2017

Am 04.06.2017 um 22:07 schrieb crow:
> On Sun, Jun 4, 2017 at 9:11 PM, Heiner Kallweit <hkallweit1 at> wrote:
>> Am 04.06.2017 um 17:59 schrieb crow:
>>> Hi,
>>> Posting to list as requested. I get call trace when using WiFi on Khadas VIM Pro, which comes with an AP6255. Firstly i wrote about this directly to Martin Blumenstingl, and he pointed me for this to post here.
>>> This looks like a bug in the meson-gx-mmc.c (SD/SDIO/eMMC) driver [1]. Martin last successful test was with kernel 2.11.
>>> How to reproduce this:
>>> mainline kernel 4.12.0-rc3 (using ArchLinuxARM arm8v generic rootfs)
>>> Khadas VIM Pro nvram file [2]
>> I have been in contact with others using AP6255-based SDIO WiFi with this driver. After the recent version of the driver
>> was released I didn't hear back from them so I assume WiFi is working fine for them.
>> The firmware image you use seems to be for Android. Not sure which firmware the others are using.
>> This might be a potential reason for the issue.
> I did not find any other firmware to check. If you same some links can
> you please share.
>>> Enable WiFI (connected to 5GHZ AP)
>>> just do an SSH to Khadas VIM Pro device and you will get these call trace [3] , eventually you get login prompt but it is very slow login.
>> The log shows that first HW reports a failed write transfer (status 0x0100) and then an unexpected interrupt occurs (host->cmd being NULL).
>> Apart from the firmware the failed transfer might also be caused by e.g. a too high frequency.
> Too high frequency of what? I am testing this on an 5GHz AP, i could
> test it with 2,4GHz to, but need to find that box.
Sorry, I meant the SDIO bus frequency here (max value is defined via device tree).

>> Would be interesting to hear what's the latest kernel version (or even better: a bisect) working for you.
> Well this could be an problem, as Khadas VIM support was added in
> 4.12, and I actually don't have any kernel working before, and this
> was first try with WiFi.
> I used same firmware which Martin did in his patch in patchwork [4].
> Maybe not related to WiFi firmware but Khadas support uses same
> android source for BT on ubuntu see [5].
>> I'm using a Odroid-C2 where SDIO isn't available, so I'm not able to test.
>>> [1]
>>> [2]
>>> [3]
> [4]
> [5]

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