From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Drake Subject: Re: MMC runtime PM patches break libertas probe Date: Mon, 30 May 2011 08:01:41 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from mail-px0-f179.google.com ([209.85.212.179]:48586 "EHLO mail-px0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949Ab1E3HBm (ORCPT ); Mon, 30 May 2011 03:01:42 -0400 Received: by pxi2 with SMTP id 2so2293260pxi.10 for ; Mon, 30 May 2011 00:01:42 -0700 (PDT) In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ohad Ben-Cohen Cc: linux-mmc@vger.kernel.org On 30 May 2011 07:52, Ohad Ben-Cohen wrote: > On Sun, May 29, 2011 at 7:21 PM, Daniel Drake wrote: >> It's certainly possible that there's something weird about the >> hardware in question, but we *are* able to successfully power down and >> up the card with a hacky rfkill driver that calls mmc_stop_host / >> mmc_start_host. > > Are we talking about the XO-1.5 and the sd8686 ? Yes. > Last we talked, we found out runtime PM didn't work because the sd8686 > required an additional manipulation of an external reset gpio line, > and that the only reason OLPC could power it down/up was this patch: > > http://dev.laptop.org/git/olpc-2.6/commit/?h=olpc-2.6.35&id=e9bee721fb0cc303286d1fe5df4930ce79b0b1e0 My further investigation here suggests that this change is not necessary. It was added in response to a separate (hard-to-reproduce) issue and it was never known if it would actually fix that issue, it was more of a guess. We don't have any convincing evidence that it helps, so it will be dropped in future. Anyway, just to be sure, I tried combining this hack with runtime PM, and also as a regulator, and it didn't help anything. runtime PM still fails to power up the card. Sorry for leading you down the wrong path there. > does mmc_stop_host+mmc_start_host > work for you without manipulating that reset gpio ? Yes. ... > Otherwise, submit :) Thanks for reviewing, I'll go ahead and clean it up. You didn't comment on the added mmc_select_voltage() call. Is that one also sensible? Thanks, Daniel