2013/3/22 Huang Changming-R66093 <r66093@xxxxxxxxxxxxx>: > >> -----Original Message----- >> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Kevin Liu >> Sent: Friday, March 22, 2013 2:55 PM >> To: Huang Changming-R66093 >> Cc: linux-mmc@xxxxxxxxxxxxxxx; Chris Ball; Ulf Hansson >> Subject: Re: [PATCH 1/3i v6] MMC/SD: Add callback function to detect card >> >> 2013/3/22 Huang Changming-R66093 <r66093@xxxxxxxxxxxxx>: >> >> Jerry, >> >> >> >> Function _mmc_detect_card_removed should only be called when card >> >> insert/removal or i/o error occur unless POLLING is used(called once >> >> per second). So it should _not_ impact performance much. >> > [jerry] >> > No, your understanding is wrong. >> > Function "_mmc_detect_card_removed " is called to check if our card has >> been removed when driver run the function "mmc_rescan" every time. >> > >> >> But when will mmc_rescan be called? >> Besides boot up, only when card status change it will be called. >> So usually it should _not_ be called frequently. > [jerry] > For poll mode, how to know card status changed? > The answer is "mmc_rescan". > maybe you could read the last two lines of this function ago. > I mentioned this in my first response "unless POLLING is used(called once per second)". I was a bit confused firstly. I think slot-gpio is a better solution, with which you don't need the every second polling. >> >> POLLING is poor for performance, why not change to slot-gpio if host >> >> is broken for card detect. >> > [jerry] >> > Some our boards can't support interrupt mode to detect card >> insert/removable, so we unify the poll mode. >> > >> >> Not support gpio interrupt? >> I think you only don't support sdh host interrupt. > -- 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
