Re: USB hub provoked slowdown.

On 5 Nov 2007, at 12:59, Ian FREISLICH wrote:

> Hi
>
> On my old home system running 7.0-BETA1 - Dual P3-800, when I plug
> my in-monitor (HP L1955) USB hub into my shiny new USB2 PCI card,
> my entire system starts wading through molasas.
>
> By this I mean, for example:
>
> mplayer: ~30% cpu
> xorg: ~12% cpu
>
> Then insert molasas inducing HP monitor uhub
>
> mplayer: ~99% cpu
> xorg: ~75% cpu
>
> Removing the hub lets the previous consumption occur.
>
> What I don't understand is why these seemingly unrelated to usb
> processes cpu utilisation goes up when I plug the uhub in.  Interrupt
> and system CPU usage remains unchanged.  Plugging the keyboard and
> mouse directly into the usb card works fine.
>
> I am at a loss.
>
> The USB card is identified as:
>
> uhci0_at_pci0:0:12:0:      class=0x0c0300 card=0x30381106  
> chip=0x30381106 rev=0x61
> hdr=0x00
>    vendor     = 'VIA Technologies Inc'
>    device     = 'VT82xxxxx UHCI USB 1.1 Controller (All VIA Chipsets)'
>    class      = serial bus
>    subclass   = USB
> uhci1_at_pci0:0:12:1:      class=0x0c0300 card=0x30381106  
> chip=0x30381106 rev=0x61
> hdr=0x00
>    vendor     = 'VIA Technologies Inc'
>    device     = 'VT82xxxxx UHCI USB 1.1 Controller (All VIA Chipsets)'
>    class      = serial bus
>    subclass   = USB
> ehci0_at_pci0:0:12:2:      class=0x0c0320 card=0x31041106  
> chip=0x31041106 rev=0x63
> hdr=0x00
>    vendor     = 'VIA Technologies Inc'
>    device     = 'VT6202/12 USB 2.0 Enhanced Host Controller'
>    class      = serial bus
>    subclass   = USB
>
> The monitor's hub is identified as follows according to usbdevs:
>
> port 2 addr 2: full speed, self powered, config 1, product  
> 0x2504(0x2504), vendor 0x0424(0x0424), rev 0.01

A couple of questions:
1) Are you using kbdmux?
2) Does the CPU usage go up when you plug the keyboard OR when you  
plug the mouse ? Or when both are connected?
3) Do you see any change just by plugging the USB hub?

Regards.
--
Rui Paulo