Re: External USB2 HDD affects speed hda

From: Rene Herman
Date: Wed Jun 01 2005 - 17:44:32 EST


Rene Herman wrote:

David Brownell wrote:

The experiment: verify that only the RUN bit is set on your machine
too. If "Periodic" and/or "Async" bits are set, then the controller
is _supposed_ to be issuing DMA transfers over PCI, so less bandwidth
will be available. Otherwise, not.

[ snip ]

and one after switching on the USB2 HDD, when the hdparm result for hda has dropped to 42 MB/s:

===
bus pci, device 0000:00:09.2 (driver 10 Dec 2004)
EHCI 1.00, hcd state 1
structural params 0x00002204
capability params 0x00006872
status a008 Async Recl FLR

Only see that "Async" now while rereading. Did you mean that one? If so, I'm right now catting the registers file and that "Async" is toggling on and off continuously. 4 cats in a row:

status 0008 FLR
status 8008 Async FLR
status a008 Async Recl FLR
status 0008 FLR

Rene.
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