On 06/06/16 06:07, Shawn Lin wrote: > JEDEC eMMC v5.1 introduce an autonomously initiated method > for background operations. > > Host that wants to enable the device to perform background > operations during device idle time, should signal the device > by setting AUTO_EN in BKOPS_EN field EXT_CSD[163] to 1b. When > this bit is set, the device may start or stop background operations > whenever it sees fit, without any notification to the host. > > When AUTO_EN bit is set, the host should keep the device power > active. The host may set or clear this bit at any time based on > its power constraints or other considerations. > > Currently the manual bkops is only be used under the async req > circumstances and it's a bit complicated to be controlled as the > perfect method is that we should do some idle monitor just as rpm > and send HPI each time if receiving rd/wr req. But it will impact > performance significantly, especially for random iops since the > weight of executing HPI against r/w small piece of LBAs is > nonnegligible. > > So we now prefer to select the auto one unconditionally if supported > which makes it as simple as possible. It should really good enough > for devices to manage its internal policy for bkops rather than the > host, which makes us believe that we could achieve the best > performance for all the devices implementing auto bkops and the only > thing we should do is to disable it when cutting off the power. Do you know if there is really a requirement to do that? Because then, what is the point of power off notification? And why is AUTO_EN persistent across power failure? -- 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
