I'm not sure what you mean -- where does it do that? It often reads the current USBCMD register, changes some bits there, and then writes the result back ... that's how it issues commands to that hardware. For example, to turn the async or periodic schedule processing on or off; or to reduce the interrupt latency. And in a few spots it forces a read of some register (like USBCMD) to make sure that any posted PCI writes have made it to the hardware.
But I don't recall ever wanting to write the same value back, without changing anything. It's not that it'd be wrong, it's just that it'd be pointless! :) - Dave ----- Original Message ----- From: "Alex Huang" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, October 23, 2001 6:38 PM Subject: [linux-usb-devel] EHCI Question > Hi All, > On the EHCI driver , why the driver will read the USBCMD register then > write the same value back more often ?? > > > Alex > > _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
