From marcelo@kvack.org Thu Jan 25 13:13:28 2007 From: Marcelo Tosatti Date: Sun, 21 Jan 2007 19:45:59 -0200 Subject: USB: switch ehci-hcd to new polling scheme To: David Brownell Cc: linux-usb-devel@lists.sourceforge.net, Marcelo Tosatti , Alan Stern , Greg KH , Jordan Crouse , Christopher Blizzard , , Ingo Molnar Message-ID: <20070121214559.GA28885@dmt> Content-Disposition: inline Switch ehci-hcd to use the new polling scheme, which reports root hub status changes via the interrupt handler, in an asynchronous fashion. Doing so disables polling for status changes (whose handler is rh_timer_func). Tested on a Geode GX machine, which is now capable of running at =~ 5 timer interrupts per second (in the -rt tree), resulting in significant power savings. Signed-off-by: Marcelo Tosatti Cc: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- gregkh-2.6.orig/drivers/usb/host/ehci-hcd.c +++ gregkh-2.6/drivers/usb/host/ehci-hcd.c @@ -501,6 +501,9 @@ static int ehci_run (struct usb_hcd *hcd u32 temp; u32 hcc_params; + hcd->uses_new_polling = 1; + hcd->poll_rh = 0; + /* EHCI spec section 4.1 */ if ((retval = ehci_reset(ehci)) != 0) { ehci_mem_cleanup(ehci); @@ -574,7 +577,7 @@ static int ehci_run (struct usb_hcd *hcd static irqreturn_t ehci_irq (struct usb_hcd *hcd) { struct ehci_hcd *ehci = hcd_to_ehci (hcd); - u32 status; + u32 status, pcd_status = 0; int bh; spin_lock (&ehci->lock); @@ -624,6 +627,7 @@ static irqreturn_t ehci_irq (struct usb_ /* remote wakeup [4.3.1] */ if (status & STS_PCD) { unsigned i = HCS_N_PORTS (ehci->hcs_params); + pcd_status = status; /* resume root hub? */ if (!(ehci_readl(ehci, &ehci->regs->command) & CMD_RUN)) @@ -670,6 +674,8 @@ dead: if (bh) ehci_work (ehci); spin_unlock (&ehci->lock); + if (pcd_status & STS_PCD) + usb_hcd_poll_rh_status(hcd); return IRQ_HANDLED; }