Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966537Ab3E2Tin (ORCPT ); Wed, 29 May 2013 15:38:43 -0400 Received: from mga09.intel.com ([134.134.136.24]:64221 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966298Ab3E2Tid (ORCPT ); Wed, 29 May 2013 15:38:33 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,765,1363158000"; d="scan'208";a="321499521" Date: Wed, 29 May 2013 12:38:28 -0700 From: Sarah Sharp To: Julius Werner Cc: Shawn Nematbakhsh , Alan Stern , linux-usb@vger.kernel.org, Greg Kroah-Hartman , LKML , Don Zickus , Oliver Neukum Subject: Re: [PATCH] usb: xhci: Disable runtime PM suspend for quirky controllers. Message-ID: <20130529193828.GK32085@xanatos> References: <20130524210503.GC15788@xanatos> <20130528205842.GE32085@xanatos> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1693 Lines: 35 On Tue, May 28, 2013 at 02:41:18PM -0700, Julius Werner wrote: > The policy we want to achieve is to disable runtime PM iff there is a > device connected that doesn't have persist_enabled or a reset_resume() > handler and whose parent/root hub resets on resume, right? Makes sense. However, not all distros may want that policy, so there should be a way to change that policy via sysfs. Some distros may choose to take the power savings over having a particular USB device work, especially in the server market. Don, Oliver, what do you think of this patch: http://marc.info/?l=linux-usb&m=136941922715772&w=2 Julius is proposing to limit the scope of the patch a bit, but the impact will still be that TI hosts will be active more often than not. > So couldn't > we remove the HCD-specific XHCI_RESET_ON_RESUME and set the (existing) > generic USB_QUIRK_RESET_RESUME on the root hub instead? Then we could > handle all of this in the USB core (during device initialization and > when changing persist_enabled through sysfs) by just checking for > udev->reset_resume on all parent hubs of the device in question (and > use pm_runtime_get/put() on said device to prevent its parents from > suspending as appropriate). Alan, what happens if we set USB_QUIRK_RESET_RESUME on the roothub? I don't think that currently translates into the host controller's Reset register getting written, which is what I think Julius is proposing. Sarah Sharp -- 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/