Messages in this thread Patch in this message | | | Date | Tue, 13 May 2003 10:30:44 -0700 | From | Greg KH <> | Subject | Re: 2.5.69 Interrupt Latency |
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On Tue, May 13, 2003 at 10:35:07AM -0500, Paul Fulghum wrote: > On Tue, 2003-05-13 at 10:26, Alan Stern wrote: > > > Putting in a sanity check for the global suspend state will be very easy. > > But I would like to point out that this "global suspend" does not refer to > > the entire system, only the USB bus. > > That is a problem then, because the delay can still > occur during normal system operation.
Ok, can you try the attached patch and see if it causes your latency problem to go away?
thanks,
greg k-h
--- a/drivers/usb/host/uhci-hcd.c Sun May 4 23:49:54 2003 +++ b/drivers/usb/host/uhci-hcd.c Tue May 13 10:26:02 2003 @@ -1947,6 +1947,11 @@ dbg("%x: wakeup_hc", io_addr); + /* Verify that we really should wake up the hc */ + status = inw(io_addr + USBCMD); + if (!(status & USBCMD_EGSM)) + return; + /* Global resume for 20ms */ outw(USBCMD_FGR | USBCMD_EGSM, io_addr + USBCMD); wait_ms(20); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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