Jonathan Thorpe wrote:
Greetings,

A few days ago, Asrock released a new BIOS for the motherboard that I have
been using as my primary test computer for the VT8235. The BIOS changelog
doesn't specifically mention any improvements to PCI handling and
everything else appears to be fairly unrelated (except for the USB boot
which now works really well) - see
http://www.asrock.com.tw/support/bios/Info/K7VT2_Info.txt

Looks like the BIOS changelog might be incomplete then ... this is a rather curious discovery.


Since the update, the computer has not hang once during data read/write
operations to the USB 2.0 HDD on the VIA EHCI controller. I thought this
would have been the recent EHCI code if anything, but after reverting back
to the previous version of the BIOS (1.20), the computer was back to
writing perfectly, then hanging when the read operations were performed on
the USB 2.0 HDD. The only way I could get it to hang was unloading and
loading the EHCI driver twice - this is understandable and not normal
practice.

Actually, not understandable to me. I've never seen it, and would not expect it ever to happen.


The VIA EPIA-M and EPOX are still two problem computers with the EHCI and
may be suffering from something that the BIOS configures improperly. When
I updated the BIOS, I ensured that all settings remained the same to avoid
any confusion and the same IRQs are assigned to the same devices. Could
this case provide any clues as to why the VT8235 still hangs like crazy on
some computers?

Yes, but likely the details of the clue are available exclusively to the folk who updated that BIOS ...


Is there any data that I can provide which may provide some clues?

On my system that's currently running 2.4.21-pre5-ac3, here are some logs
I created. The files starting in 120 are from the computer running the
BIOS 1.20, and the files starting in 130 are those which are from the
computer running BIOS 1.30:

http://users.bigpond.net.au/linux/ehci/120_dmesg
http://users.bigpond.net.au/linux/ehci/130_dmesg

The main worrisome thing there is that PCI warning message that says it expected a PCI cache line size of 16 bytes; the right number is 64 bytes, and that wrong value could lead to some problems. You might want to comment out the line in "ehci-hcd.c" that calls pci_set_mwi().


http://users.bigpond.net.au/linux/ehci/120_lspci-vvv
http://users.bigpond.net.au/linux/ehci/130_lspci-vvv

http://users.bigpond.net.au/linux/ehci/120_interrupts
http://users.bigpond.net.au/linux/ehci/130_interrupts

I intend on recompiling the kernel later on today with EHCI debugging
messages; will these be of any help?

Likely not, since the failure is more subtle than those diagnostics are intended to report.

- Dave



Thanks,
Jonathan Thorpe






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