Re: MMIO ioremap() error with PCI passthrough

[Andy Burns <lists.xensource.com@adslpipe.co.uk>]

On 01/07/2008 18:15, Keir Fraser wrote:

> Good idea. This kind of thing can be an honest mistake which would normally
> never cause a problem running natively.

I've asked the linuxtv folk if they are interested in a patch.

> Does the card work at all up to this point (first 40s)? 

Well, if I modprobe the saa7134.ko and saa7134_dvb.ko
I get the /dev/video0 and /dev/dvb/adapter0 devices created

But if I try to scan for TV channels with

# dvbscan /usr/share/dvb/dvb-t/uk-Waltham  > ~/.tzap/channels.conf

I get "Unable to query frontend status", so the device doesn't seem to 
be functioning.

> Any sign of life after the message prints?

The machine doesn't die when the stray interrupt fires, in fact I can 
rmmod the module and modprobe it again, the error repeats after another 
40 seconds.

> This would indicate either that Xen/pciback has got irq routing wrong for
> this line (so the wrong interrupts are being delivered to the driver) or
> that for some other reason the driver has decided that there was no work to
> be done in response to the interrupt. Could the irq line for this device be
> a shared line? 

I did wonder how (or if) shared interrupts would work.

Given the relatively high number of devices on the motherboard and 
PCI-X/PCI/PCIe cards I suspect it will have to be shared.

Here is a brief lspci

00:00.0 Host bridge: Intel Corporation 82X38 Express DRAM Controller 
(rev 01)
00:01.0 PCI bridge: Intel Corporation 82X38 Express Host-Primary PCI 
Express Bridge (rev 01)
00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #4 (rev 02)
00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #5 (rev 02)
00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #6 (rev 02)
00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI 
Controller #2 (rev 02)
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio 
Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express 
Port 1 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express 
Port 3 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express 
Port 4 (rev 02)
00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express 
Port 5 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI 
Controller #3 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI 
Controller #1 (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)
00:1f.0 ISA bridge: Intel Corporation 82801IR (ICH9R) LPC Interface 
Controller (rev 02)
00:1f.2 SATA controller: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 
port SATA AHCI Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller 
(rev 02)
01:00.0 VGA compatible controller: ATI Technologies Inc RV370 [Sapphire 
X550 Silent]
01:00.1 Display controller: ATI Technologies Inc RV370 secondary 
[Sapphire X550 Silent]
02:00.0 IDE interface: Marvell Technology Group Ltd. 88SE6145 SATA II 
PCI-E controller (rev a1)
03:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E 
Gigabit Ethernet Controller (rev 12)
04:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E 
Gigabit Ethernet Controller (rev 12)
05:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X 
Bridge (rev 06)
05:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X 
Bridge (rev 06)
07:01.0 SCSI storage controller: Marvell Technology Group Ltd. 
MV88SX6081 8-port SATA II PCI-X Controller (rev 09)
08:01.0 Multimedia controller: Philips Semiconductors SAA7130 Video 
Broadcast Decoder (rev 01)
08:03.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host 
Controller (rev c0)

Looks like the PCI slot with the tuner shares IRQ17 with the PCI-X slot 
used by my 8xSATA card.

07:01.0 SCSI storage controller: Marvell Technology Group Ltd. 
MV88SX6081 8-port SATA II PCI-X Controller (rev 09)
         Subsystem: Marvell Technology Group Ltd. Unknown device 11ab
         Interrupt: pin A routed to IRQ 17

08:01.0 Multimedia controller: Philips Semiconductors SAA7130 Video 
Broadcast Decoder (rev 01)
         Subsystem: Compro Technology, Inc. Videomate DVB-T200
         Interrupt: pin A routed to IRQ 17

I can try to move the tuner card to the other PCI slot, but I suspect it 
will just share with something else instead, besides I planned to 
populate both PCI slots with tuners for passthrough, once I got the 
first one working.

> You could try disabling the spurious irq logic in
> kernel/irq/spurious.c, and then see if the device works and also what the
> irq rate looks like in /proc/interrupts.

I'll have a go at that.