From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Hansson Subject: Re: [PATCH 2/2] mmc: sdhci-pci: add runtime pm support Date: Thu, 6 Oct 2011 16:39:00 +0200 Message-ID: <4E8DBD84.8070103@stericsson.com> References: <1317645214-12316-1-git-send-email-adrian.hunter@intel.com> <1317645214-12316-3-git-send-email-adrian.hunter@intel.com> <4E8C70D7.6080305@stericsson.com> <4E8D5D07.4010604@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eu1sys200aog113.obsmtp.com ([207.126.144.135]:41577 "EHLO eu1sys200aog113.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754778Ab1JFOji (ORCPT ); Thu, 6 Oct 2011 10:39:38 -0400 In-Reply-To: <4E8D5D07.4010604@intel.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Adrian Hunter Cc: Chris Ball , linux-mmc , Linus WALLEIJ > > It has been discussed on the list before that the host controller driver should > be solely responsible for host controller power. OK I see, sorry that I missed that discussion earlier! Anyway this should be feasible as well even it might mean duplicated code in each host driver. A positive side is that it gets more flexible for each host driver. > >> >> Moreover 1: >> I have noticed the pm_runtime support is implemented for sdio and when having >> MMC_CAP_POWER_OFF_CARD. This needs to be "cleaned up" after such a change. It >> might also conflict with your patch considering "moreover 2" below. > > No. The card and the host controller are separate devices. The card can be > powered up when the host controller is off and vice versa. They are not > inter-dependent in that regard. I see your point, but it is somewhere here it is getting a bit "messy". :-) If I understand correct, you mean that the mmc/sd/sdio framework shall be responsible of handling power management of the bus/card devices. In other words the framework shall itself decide when it is feasible of doing mmc_power_restore_host, mmc_power_save_host, mmc_suspend_host, mmc_resume_host. This is not the case right now, since most host drivers are normally in control of calling these functions themselves. Should this be moved to the framework then? > >> Moreover 2: >> dev_pm_ops with runtime functions, are implemented for the mmc bus (core/bus.c). >> Maybe this should be moved from the responsibility of the bus into the mmc host >> drivers instead!? I think it makes more sense to leave such decisions as doing >> "mmc_power_save_host/mmc_power_restore_host" to each mmc host driver. Just >> because we get runtime suspended that does not have to mean we wnat to do >> mmc_power_save_host... What do you think? > > Again, this has been discussed before on the list, that the power management of > the card is something that only upper layers control e.g. sdio function driver > I got it, thanks a lot for your answers and feedback! > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > BR Ulf Hansson