Messages in this thread | | | Date | Thu, 2 Jun 2005 03:23:09 +0200 (CEST) | From | Mikulas Patocka <> | Subject | Re: External USB2 HDD affects speed hda |
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On Wed, 1 Jun 2005, David Brownell wrote:
> On Wednesday 01 June 2005 3:33 pm, Rene Herman wrote: > > 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 > > Tbat's strange ... shouldn't do that unless someone's issuing > requests to the bus. Which shouldn't happen if no devices are > hooked up to that bus. If the "command" register isn't turning > on async requests, that's particularly strange. > > - Dave
Hi
Didn't you just forget to set H-bit in exactly one queue head? If there's no entry with H-bit set, controller will loop over list of empty heads again and again.
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