Re: PROBLEM: Nvidia OHCI chipset MCP78S (Geforce 8200) hangs on >1Mbit transfers if noapic/acpi=noirq is missing

[Alan Stern]

On Mon, 6 Jul 2009, Zbigniew Luszpinski wrote:

> I hope I find here someone who wrote or know Linux ohci driver so he/she knows 
> how to slow down ohci bulk/iso IO operations without breaking hotplug.

The speed of iso operations cannot be changed, because the transactions 
have to occur at a specified interval.

OHCI doesn't provide any way to slow down bulk operations either, once 
a bulk URB has been submitted.  The best you can do is slow down the 
rate of submission.  But you already tried that and it didn't work.

> It looks Linux ohci driver is more aggressive on ohci IO than windows one so 
> making Linux less timing demanding would help my MCP78S keep working.

I suspect you're looking in the wrong direction.  There's probably 
something wrong at a deeper level, in the chipset drivers for instance.

Alan Stern

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