From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 8/9] ata: Add support for the Tegra124 SATA controller Date: Tue, 17 Jun 2014 11:37:49 -0600 Message-ID: <53A07CED.7010503@wwwdotorg.org> References: <1401881559-18469-1-git-send-email-mperttunen@nvidia.com> <1470404.13mIFv0Hnj@amdc1032> <53A0686F.4000303@wwwdotorg.org> <6652229.bPNq3Yp8If@amdc1032> <53A07CA4.7080206@kapsi.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <53A07CA4.7080206-/1wQRMveznE@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mikko Perttunen , Bartlomiej Zolnierkiewicz Cc: Mikko Perttunen , thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ide-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ide@vger.kernel.org On 06/17/2014 11:36 AM, Mikko Perttunen wrote: > On 06/17/2014 08:04 PM, Bartlomiej Zolnierkiewicz wrote: >> >> Hi, >> >> On Tuesday, June 17, 2014 10:10:23 AM Stephen Warren wrote: >>> On 06/17/2014 06:14 AM, Bartlomiej Zolnierkiewicz wrote: >> >> [...] >> >>>>> +static struct platform_driver tegra_ahci_driver = { >>>>> + .probe = tegra_ahci_probe, >>>>> + .remove = ata_platform_remove_one, >>>>> + .driver = { >>>>> + .name = "tegra-ahci", >>>>> + .owner = THIS_MODULE, >>>>> + .of_match_table = tegra_ahci_of_match, >>>>> + }, >>>> >>>> This driver lacks PM suspend/resume support. I assume that >>>> the Tegra124 platform also doesn't support suspend/resume yet >>>> (if so a comment in the driver code about this would be useful), >>>> otherwise the driver should be fixed. >>> >>> We do have basic system suspend/resume support. However, I don't think >>> missing suspend/resume in an individual driver should stop it from being >>> merged. It can certainly be added later. >> >> There should be at least FIXME in the driver explaining the situation and >> I would really prefer to have PM support added when the driver is still >> "hot" (meaning there are people actively working on it) instead of >> possibly >> having to chase people months/years later when they have already moved on >> and are working on something else. Please also note that adding PM >> support >> should be quite simple if the driver is designed correctly. > > AFAIK, the deepest level of suspend currently supported on upstream is > LP1, for which the driver doesn't need to do anything. Only when we go > to LP0 the driver will need to save/reload registers and stuff. Yes, it's generally true that no SoC register state is lost during suspend, only CPU state.