4.10-rc3 rpi issues

Peter Robinson pbrobinson at gmail.com
Tue Mar 14 09:48:27 PDT 2017

On Wed, Jan 11, 2017 at 2:29 PM, Gerd Hoffmann <kraxel at redhat.com> wrote:
>   Hi,
> Moved my pile of patches forward to 4.10-rc3, so I can see what actually
> landed in the 4.10 merge window, and go try send/resend patches for 4.11
> Trapped into a bunch of problems:
> usb is flaky.  raspberry pi 2 b.  Has a edimax wifi dongle, and that
> stopped working.  rtl8xxxu driver.  Doesn't find any wifi networks.  usb
> keyboard has problems too, looses keys now and then, which makes me
> think this is more a usb than a wifi problem.  I had that before, with
> the 4.8 kernels.  4.9 works fine.  Now with 4.10-rc3 the problems are
> back :(  Anyone seen this too?  Any clues what this might be?

So as a follow up to this. I was playing with your patches for the
other MMC driver. Fedora builds as much modular as possible, saw a
dmesg with the new kernel module about using PIO mode due to no DMA,
forced the DMA module into the initrd and that problem goes away and
performance improves on MMC (both SD and wifi) for 4.11rc2.

Went and tried the same on a RPi3 with a 4.10 kernel without with MMC
patches to see what the improvements are there in our current stable
configuration to get a gauge of no DMA -> DMA -> new driver with DMA.
With DMA loaded from the initrd I'm seeing exactly what you describe
on the usb bus along with high CPU on the kernel mmcqd process. Don't
appear to see that on 4.11 with the USB but only a little testing to

Might be a bit late but FYI.


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