call trace on Khadas VIM Pro with AP6255 WiFi

crow crow at
Sun Jun 4 13:07:04 PDT 2017

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.

> 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]


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