On Wed, Mar 03, 2010 at 03:34:09PM -0500, Alan Stern wrote: > On Wed, 3 Mar 2010, Sarah Sharp wrote: > > > On Wed, Mar 03, 2010 at 06:07:55PM +0800, Libin wrote: > > > >From d3055401927f70e4de7717138b4c8ecad8b8223a Mon Sep 17 00:00:00 2001 > > > From: Libin Yang <libin.yang@xxxxxxx> > > > Date: Wed, 3 Mar 2010 13:50:41 +0800 > > > Subject: [PATCH 3/5] xHCI: bus power management implementation > > > > > > This patch implements xHCI bus suspend/resume function hook. > > > > > > In the patch it goes through all the ports and suspend/resume > > > the ports if needed. > > > > I thought the USB core ensured that all devices were suspended before > > suspending the root hub. Alan, can you confirm? > > It does not ensure this if CONFIG_USB_SUSPEND isn't enabled. In such > cases it never suspends any ports, but it still calls the HCDs' > bus_suspend routines if CONFIG_PM is set. It's a requirement that all endpoints be stopped before you suspend/hibernate an xHCI host, but it's not a requirement that the devices be suspended. Now I'm very confused as to why the xHCI bus_suspend patch suspends all unsuspended devices, but doesn't stop their endpoint rings. Libin, Andiry, or Crane, do you have an answer? > Also, the core doesn't suspend ports that aren't enabled. This may or > may not matter for your purposes. > P.S.: Maybe this is the ranting of a grouchy old stick-in-the-mud, but > I do wish that people would trim their email replies. Is it really > necessary to post a 270-line message in order to send a 2-line question > plus 14 lines of context and signature? I'm never sure how much people read their mailing list email, and thus how much context they need when they're CC'd on an email. For you, of course you can dig the mail thread out. For other people, perhaps they've been dumping all but the interesting USB mailing list messages to /dev/null. But I will try to trim my messages for you, and other sticks in the mud like you. ;) Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
