From mboxrd@z Thu Jan 1 00:00:00 1970 From: ygardi@codeaurora.org Subject: Re: [PATCH v1 16/17] scsi: ufs: add delay before putting UFS rails in low power modes Date: Mon, 26 Oct 2015 15:08:01 -0000 Message-ID: <71145a231320062c019266176d3263b5.squirrel@www.codeaurora.org> References: <1442155977-7686-1-git-send-email-ygardi@codeaurora.org> <1442155977-7686-17-git-send-email-ygardi@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:41954 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751076AbbJZPIC (ORCPT ); Mon, 26 Oct 2015 11:08:02 -0400 In-Reply-To: Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Akinobu Mita Cc: Yaniv Gardi , Jej B , Paul Bolle , Christoph Hellwig , LKML , "linux-scsi@vger.kernel.org" , linux-arm-msm@vger.kernel.org, Santosh Y , linux-scsi-owner@vger.kernel.org, Subhash Jadavani , Gilad Broner , Dolev Raviv , Vinayak Holikatti , "James E.J. Bottomley" > 2015-09-13 23:52 GMT+09:00 Yaniv Gardi : >> We put the UFS device in sleep state & UFS link in hibern8 state during >> runtime suspaned. After this we put all the UFS rails in low power >> modes immediately but it seems some devices may still draw more than >> sleep current from UFS rails (especially from VCCQ rail) atleast for >> 500us. >> To avoid this situation, this change adds 2ms delay before putting >> these UFS rails in LPM mode. >> >> Signed-off-by: Subhash Jadavani >> Signed-off-by: Yaniv Gardi >> >> --- >> drivers/scsi/ufs/ufshcd.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index 20b4c0e..786df28 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -5694,6 +5694,15 @@ out: >> static void ufshcd_vreg_set_lpm(struct ufs_hba *hba) >> { >> /* >> + * It seems some UFS devices may keep drawing more than sleep >> current >> + * (atleast for 500us) from UFS rails (especially from VCCQ >> rail). >> + * To avoid this situation, add 2ms delay before putting these >> UFS >> + * rails in LPM mode. >> + */ >> + if (!ufshcd_is_link_active(hba)) >> + usleep_range(2000, 2100); >> + > > Shouldn't we define dev_quirks for this? as you suggested, in v2 i added a device quirk for that. > >> + /* >> * If UFS device is either in UFS_Sleep turn off VCC rail to >> save some >> * power. >> * >> -- >> 1.8.5.2 >> >> -- >> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a >> member of Code Aurora Forum, hosted by The Linux Foundation >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >