Pavel Machek wrote:

EHCI maintainter (as given by MAINTAINERS) added to CC.

> On Út 31-05-05 01:21:37, Rene Herman wrote:

[ internal IDE HDD slowdown after switching on external USB2 HDD ]

> USB controller generating extra DMA load? Try rmmoding usb to see if
> it goes away.

I was sceptical about this since the drive is idle (or even switched off 
again) but I recompiled EHCI modular and rmmodding ehci_hcd does in fact 
bring back my 50 MB/s:

				: hdparm -t /dev/hda = 50 MB/s
1. modprobe ehci_hcd		: hdparm -t /dev/hda = 50 MB/s
2. switch on USB2 drive		: hdparm -t /dev/hda = 42 MB/s
3. switch off USB drive		: hdparm -t /dev/hda = 42 MB/s
4. modprobe -r ehci_hcd		: hdparm -t /dev/hda = 50 MB/s

There would not seem to be any extra DMA load with a drive that's idle 
or switched off again though? Is the (VIA) USB2 controller playing bus 
monopolizing tricks or something sinister like that? (the speed doesn't 
drop immediately after loading ehci_hcd though, only after switching on 
the USB2 HDD)

More detail --- it's a VIA VT6212L EHCI controller, on unshared IRQ3. 
IDE0 is AMD756 on unshared IRQ14/15. The USB2 HDD does 30 MB/s (after a 
hdparm -a 1024; with the default 256 it's 25MB/s) which I did think was 
a very good speed.

lspci -vv attached, in case it's useful.

Many thanks in advance to anyone for any additional insight...

Rene.