Re: Regression in kernel 4.2.3+ (relative to 4.1.10) on AMD 990FX system with IOMMU enabled

[Laine Stump <laine-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 11/04/2015 04:08 PM, Alex Williamson wrote:
> On Wed, 2015-11-04 at 12:24 -0500, Laine Stump wrote:
>> Last week I upgraded my Fedora 22 AMD 990FX system from kernel 4.1.10 to
>> 4.2.3 (standard Fedora builds) and multiple devices stopped working:
>>
>> * 00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] SBx00
>> Azalia (Intel HDA) (rev 40)
>>
>> * 02:00.[01] Ethernet controller: Intel Corporation 82576 Gigabit
>> Network Connection
>>
>> * 01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Cedar
>> HDMI Audio [Radeon HD 5400/6300 Series]
>>
>> (The 1st is integrated on the motherboard, the 2nd & 3rd are behind an
>> AMD RD890 pci-pci bridge. There may be other devices failing, but these
>> are the ones immediately obvious.)
>>
>> Whatever is the source of the failure, it ends up that the drivers for
>> these devices aren't loaded.
>>
>> At Alex Williamson's suggestion, I tried disabling IOMMU in the BIOS,
>> and magically all the devices resumed normal operation (except that I
>> can't do vfio device assignment because the IOMMU is disabled).
>>
>> Reverting to kernel 4.1.10 very definitely eliminates the problem. I've
>> also tried kernel 4.2.5 and it has the same problem as 4.2.3 (these
>> three are the only pre-built kernels for F22). I can provide dmesg /
>> lspci output from each of these, or any other debug info anyone might
>> like me to gather.
>
> I built a 4.2.3 kernel for my 990fx system and can't seem to reproduce
> it.  Does 'lspci -k' for those devices show any driver?

00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] SBx00 
Azalia (Intel HDA) (rev 40)
	Subsystem: Gigabyte Technology Co., Ltd Device a132
	Kernel modules: snd_hda_intel
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Cedar HDMI 
Audio [Radeon HD 5400/6300 Series]
	Subsystem: Gigabyte Technology Co., Ltd Device aa68
	Kernel modules: snd_hda_intel
02:00.0 Ethernet controller: Intel Corporation 82576 Gigabit Network 
Connection (rev 01)
	Subsystem: Intel Corporation Gigabit ET Dual Port Server Adapter
	Kernel driver in use: igb
	Kernel modules: igb
02:00.1 Ethernet controller: Intel Corporation 82576 Gigabit Network 
Connection (rev 01)
	Subsystem: Intel Corporation Gigabit ET Dual Port Server Adapter
	Kernel modules: igb

/sys/devices/pci0000:00/0000:00:04.0/0000:02:00.0 does show a link from 
driver to ........drivers/igb, but .......:02::00.1 doesn't have a link, 
and neither of them shows up in /sys/class/net.

Similarly for 01:00.[01] (which are behind the PCI to PCI bridge at 
00:02.0), the .0 device does have a link to the radeon driver, but the 
.1 device (which is the sound device on the radeon video card) has no 
driver link.

And 00:14.2 (the motherboard integrated sound device) shows no driver 
link in sysfs either.

> Does 'lsmod'
> show the drivers loaded, igb and snd_hda_intel?  If not, does manually
> modprobe'ing either of those drivers change anything?

Both of those drivers show up in lsmod output.

> You haven't
> installed a script that writes to driver_override or setup a
> configuration where those devices are claimed by pci-stub and forgotten
> about it, have you? (it's happened to me)

Not that I'm aware of. /etc/modules.d/local.conf had a few stray very 
old items that I'd forgotten about, but I removed those and the results 
are the same.

   Otherwise, dmesg is probably
> a good place to start.

Thanks to the uber-verbosity of systemd, this file is about 11MB. Where 
do you want me to put it?