4.10-rc3 rpi issues

[Stefan Wahren]

Hi Michael,

> Michael Zoran <mzoran at crowfest.net> hat am 11. Januar 2017 um 22:38 geschrieben:
> 
> 
> On Wed, 2017-01-11 at 16:46 +0000, Peter Robinson wrote:
> > 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?
> > > 
> > > Non-modular kernel crashes at boot.  Using that to netboot kernels
> > > cross-compiled on my faster x86 box.  Have no serial console hooked
> > > up,
> > > so no logs for now, sorry.  But maybe anyone has an idea
> > > nevertheless?
> > 
> > The Fedora built rc3 kernel seems OK. I'm using usb wifi ATM without
> > too many issues and haven't had any drop outs. I've seen some
> > interesting bits with CMA which I reported [1]. USB doesn't appear at
> > least in my testing to be any worse on the 2 or 3.
> 
> The upstream USB driver has many, many limitations.   I'm not surprised
> that you're having intermittent issues.  The issues are worse if you
> have many devices attached or you have devices of very different
> speeds(say keyboard + Wifi).

this can't be the reason because it already worked with 4.9. So it must be a regression from the many changes in 4.10.

> 
> I'm actually surprised that somebody hasn't tried to upstream the
> downstream USB driver which has less limitations.  The DWC USB
> controller is not Broadcom specific so it would apply to more then the
> RPI.  I would be interested in helping with such an effort and it may
> even be possibly to write the driver from "scratch".  The hardest part
> would be getting something like a PI Zero that doesn't have the USB hub
> soldered onto the board so that it's easy to attach a USB bus analyzer
> for better debugging.

This isn't a surprise. A new driver for a platform which is already supported by a mainline driver won't be accepted. Maybe the dwc2 driver would have a better quality for bcm2835 if the Foundation would use it instead of the separate downstream driver. Instead of adding new driver it would be better to fix the existing one.