Re: PIIX4 DMA Timeout

From: gshan
Date: Tue May 20 2008 - 21:09:33 EST

Maciej W. Rozycki wrote:
On Tue, 20 May 2008, Gavin Shan wrote:

There has one MV64460 on my board, which includes 2 PCI bridges. PIIX4 is on slot 3 of PCI1.
But now, IDE driver reported it's timeouted on DMA operation. Thanks in advance for your
PIIX4: chipset revision 1
PIIX4: not 100% native mode: will probe irqs later
ide0: BM-DMA at 0xd8000000-0xd8000007, BIOS settings: hda:pio, hdb:pio
ide1: BM-DMA at 0xd8000008-0xd800000f, BIOS settings: hdc:pio, hdd:pio
hdc: HTE721010G9AT00, ATA DISK drive
hdc: max request size: 512KiB
hdc: 195371568 sectors (100030 MB) w/7539KiB Cache, CHS=16383/255/63, UDMA(33)
hdc: cache flushes supported
hdc:<4>hdc: dma_timer_expiry: dma status == 0x26
hdc: DMA interrupt recovery
hdc: lost interrupt
hdc: dma_intr: status=0x58 { DriveReady SeekComplete DataRequest }
ide: failed opcode was: unknown
hdc: DMA disabled
ide1: reset: success
hdc2 hdc3 hdc4

It looks like some problem with interrupt routing. At least with some of
the PIIX chips I recall there was some limitation about how the IDE
interrupts had to be used for DMA to be operational. For PIO modes there
were no restrictions. Do you have chip-level documentation for your

Maciej, thank you very much for your reply. I don't think this was caused by
interrupt routing. I added lots of "printk" before following output, and saw
interrupts could be triggered correctly.

hdc: 195371568 sectors (100030 MB) w/7539KiB Cache, CHS=16383/255/63, UDMA(33)

LynxOS has been run successfully on this board, and we want port it to Linux recently.

I'm not sure which resource (I/O or Memory space) should be used for DMA operation because
all memory resources haven't been set (the flag is 0x2xxxxxxx). So my question is DMA operation
could succeed with I/O resource?

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