DMA issues with the SKGE drivers

["Benoît Dufour" <benoit.dufour@mail.com>]

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In 2024, I reported a bug about the SKGE driver, you can see it here:
https://bugzilla.kernel.org/show_bug.cgi?id=219270

Basically, the problem is that the Marvell 88E8001 on my ASUS A8V 
motherboard can only work with 32bit DMA, and if trying to use 64bit 
DMA, the NIC won't work at all and after some time, the operating system 
will become completely unresponsive (on screen tty will stop refresh, 
keyboard and mouse input will stop working too).

The fix is quite easy:

At the very end of the SKGE driver source code, the ASUS A8V motherboard 
(as well as many other boards like the ASUS A8V Deluxe) should be added 
to the list of 32bit DMA boards:
https://github.com/torvalds/linux/blob/508fed6795411f5ab277fd1edc0d7adca4946f23/drivers/net/ethernet/marvell/skge.c#L4150

In the bug report I posted in 2024, I also posted a test case:
https://bugzilla.kernel.org/attachment.cgi?id=306873&action=diff

but actually I guess a better fix would be to dynamically testing if the 
NIC support only 32bit or 64bit DMA too. If 64bit wouldn't be supported, 
this error (or a similar one) should be reported by the card:
PCI error cmd=0x117 status=0x22b0

Do you think it would be doable?

p.s.:
I know that NIC and those motherboards are very old, but I really wish 
those kinds of bugs should be fixed at some point.

-- 
Benoît Dufour

Unfortunately still a student in Computer Science


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