From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCHSET] hotplug polling, take 5 Date: Wed, 01 Nov 2006 12:02:29 +0900 Message-ID: <45480E45.1050802@gmail.com> References: <11609518461142-git-send-email-htejun@gmail.com> <45480158.2030501@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ug-out-1314.google.com ([66.249.92.175]:39259 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S1946042AbWKADCi (ORCPT ); Tue, 31 Oct 2006 22:02:38 -0500 Received: by ug-out-1314.google.com with SMTP id 32so1629570ugm for ; Tue, 31 Oct 2006 19:02:37 -0800 (PST) In-Reply-To: <45480158.2030501@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: alan@lxorguk.ukuu.org.uk, linux-ide@vger.kernel.org Jeff Garzik wrote: > Tejun Heo wrote: >> Hello, all. >> >> This is the fifth take of hotplug polling patchset. This take doesn't >> contain any real change than rebasing over the current upstream[U]. >> PMP patchset will be posted soon on top of this patchset and I wanted >> to avoid confusion by posting patchsets in order. >> >> As the name implies, this patchset implements hotplug by polling. >> hp-poll is used to >> >> * Monitor ports EH gave up. When EH gives up on a port, it freezes >> the port to protect the rest of the system from it. The user used >> to have to issue manual scan to retry the port. hp-poll can monitor >> such port and retry it when hotplug event is detected. This is also >> used by PMP support. >> >> * Support hotplug on controllers which can report hotplug conditions >> but cannot raise interrupt. > > Patchset seems sane. I'll need to re-read patch #1 in depth, but I give > everything a tentative ACK for now. > > My biggest concern is power usage. On laptops for example, the 99% > common case is that the user will never hot[un]plug a drive, so we > shouldn't waste power bothering with poking disabled ports. Link powersave patchset should handle that together but I'm still not sure what to do w/ user interface (which sysfs node to use). Also, controllers which are used on laptops && use hp-poll by default are sata_nv (old ones) and some variant of sata_sil used in ati chipset. So, it shouldn't cause trouble for most laptop users. -- tejun