Chris, (Sorry for top posting) Seems we have a intel intern disagreement. Could we have maintainer opinion on this ? Regards, Pierre > -----Original Message----- > From: Dong, Chuanxiao > Sent: Wednesday, January 19, 2011 10:04 AM > To: Tardy, Pierre; linux-mmc@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; cjb@xxxxxxxxxx; ohad@xxxxxxxxxx > Subject: RE: [PATCH v1 1/3]mmc: implemented runtime pm for mmc host > > Hi Pierre, > I think the runtime pm should not have any dependency with clock gating. Even the MMC driver won't > clock gate SD/MMC card, host controller should still enter runtime suspend state, right? > So if auto suspended delay could be changed by user, then we can use pm_suspend_schedule to specify > the latency which is longer than 8 clock cycle. > > Thanks > Chuanxiao > > -----Original Message----- > > From: Tardy, Pierre > > Sent: Wednesday, January 19, 2011 12:39 AM > > To: Dong, Chuanxiao; linux-mmc@xxxxxxxxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx; cjb@xxxxxxxxxx; ohad@xxxxxxxxxx > > Subject: RE: [PATCH v1 1/3]mmc: implemented runtime pm for mmc host > > > > > > I'm also worried about this patch not taking in account the 8 clock cycles before > > > > shutting down the clock, contrary to the clock gating fw. > > > > If you power down hc, you will also gate the clock. So the sdio protocol might not > > be > > > > strictly followed. > > > As mmc spec said, 8 clock cycles is needed. That is right. > > > But I think if we have set the auto suspended delay for host, runtime pm core > > could make sure host to > > > wait at least the auto suspended delay before shutting down the power of the > > device. So if the auto > > > suspended delay is longer than 8 clock cycles, the mmc protocol can be followed, > > right? > > I disagree. You cannot enforce this. It depends on clock speed, that can vary with > > sdio cards. > > User can change the autosuspend delay to whatever he wants, it should just > > change performance, but not functionality. > > > > Why don't you just take my clock gating version? > > Its working well, I'm using this for 2 weeks, and follow the linux-mmc latest > > improvement. > > > > Regards, > > Pierre > > --------------------------------------------------------------------- Intel Corporation SAS (French simplified joint stock company) Registered headquarters: "Les Montalets"- 2, rue de Paris, 92196 Meudon Cedex, France Registration Number: 302 456 199 R.C.S. NANTERRE Capital: 4,572,000 Euros This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
