> > > First of all I would like to thank all contributors for figuring out
> > > the bits and pieces that make the F28 images bootable and functional
> > > on the odroid XU4.
> > >
> > > However, I noticed a couple of things after booting the F28 server image:
> > > - network interface (r8152) is connected as USB2
> > > - connecting USB3 devices seems to be hit or (mostly) miss, they are
> > > detected by the xhci driver, but usually after they are already
> > > connected as
> > > USB2
> >
> > What kernel are you running? Are you running the GA kernel
> > (4.16.something?) or have you upgraded to the latest (4.17.x) as I believe
> > both of those issues were fixed in updates kernels.
> >
> I noticed this with 4.16.3-301.fc28 included in the image, but there was the 
> same behaviour with 4.17.11-200.fc28 and rawhide 4.18.0-0.rc7.git2.1.fc29. I 
> have to say things indeed _do_ work with the default f28 kernels, you only 
> notice the performance issue by checking the output of lsusb -t, dmesg or 
> console when plugging in a USB3 device. My guess is there is some kind of 
> race between the ehci/ohci and xhci modules, with the latter being loaded too 
> slow or too late, because I do see detection messages for both USB2 and USB3 
> on the console, but usually USB2 comes first and USB3 after connection is 
> established as USB2. Since r8152 is USB based, this probably is linked.
>
> > > - it seems like only the 4 A7 cores are active and switching to the 4
> > > A15 cores is not possible
> >
> > Hmm, what does lscpu report? Also what u-boot are you using? I'm not 100%
> > sure here but I thought they were working, although with big.little I'm not
> > sure wthether they switch the whole cluster under load or just bring more
> > cpus online.
> >
> /proc/cpuinfo reports the 4 A7 cores, upon loading (load average>4) I can see 
> these cores up in /sys/.../cpu[0-3], but the A15 cores cpu[4-7] don't seem to 
> become active. Lscpu I don't know by heart, would need to check. The line " # 
> CONFIG_BL_SWITCHER is not set" changes this to all 8 cores up all the time 
> (exynos HMP). Again, the system works, but with reduced performance.
> The u-boot is the one for odroid-xu3 in the fedora 28 image, cat of .bin and 
> .dtb. Not sure if the cat is required.
>
> > > Since I noticed the Hardkernel Ubuntu image does correctly detect
> > > USB3, the issue could not be purely related to hardware design or bus
> > > power, so I decided to recompile (then) F28 kernel 4.17.11-200 with
> > > some alternative config settings, compiling in lots of USB related
> > > modules. In the end I got to the point where USB3 devices and the
> > > Ethernet chip indeed are detected as USB3, some more fiddling also
> > enabled all 8 cores simultaneously.
> > > Attached you find the kernel-local used to modify the config, which
> > > still can use some cleaning up.
> >
> > I would need a diff against the fedora config because I don't have the time 
> > to
> > work out what's changed but a lot of stuff is built in by the look of it and
> > that's not going to happen in the upstream kernel, it's also strange that 
> > it's
> > needed since others have reported it works fine, it of course could be a
> > regression but the above changes work around a regression not fix it. The
> > Hardkernel group have never been particularly upstream friendly so it's
> > anyone's guess.
> >
> > > One point now remains, these adjustments require recompiling the
> > > kernel each time an update is available, thus breaking an easy update
> > > path. Would there be a way to achieve a similar result using initramfs and
> > grub options?
> > > Thanks in advance for your comments and feedback!
> >
> > See above.
>
> Everything works, but some bits and pieces seem sub-optimal. Could anyone 
> else check the output of `lsusb -t` on an odroid XU4 with stock fedora 28/29 
> kernel? I'm mostly interested in the USB stuff, if that is sorted out, I can 
> easily evaluate cpu power. Maybe just A7 already does the trick.
>
> The main difference between both kernel configs is built in vs module for USB 
> related stuff, so this makes me wonder about modifying initramfs and/or grub 
> instead of recompiling. Any suggestion to this end would be appreciated and 
> can be tested quite fast.

man 5 dracut.conf
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