Nishanth Menon <nm@xxxxxx> writes: > Premi, Sanjeev had written, on 01/28/2010 09:21 AM, the following: >>> -----Original Message----- >>> From: linux-omap-owner@xxxxxxxxxxxxxxx >>> [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Andrew >>> Murray >>> Sent: Thursday, January 28, 2010 7:53 PM >>> To: linux-omap@xxxxxxxxxxxxxxx >>> Subject: omap3: pm: AVS enabled by default? >>> >>> Hello, >>> >>> I noticed that Smart Reflex AVS is not turned on by default - and must >>> be manually enabled from user-land through the sr_vddX_autocomp >>> controls. >>> >>> Are there any plans to enable this by default, or perhaps via a >>> KConfig >>> option in the future? >>> >>> I ask because the longer a boot time, the longer the device is running >>> without AVS (assuming it's not enabled by a boot loader) - and on a >>> mobile device with frequent power on/offs this duration could add up >>> leading to a potential missed power saving? I appreciate the saving >>> may >>> be small - but would it be worthwhile? > you may want to consider upstart and move most of your drivers into > modules rather than a static binary ;) > > But your point is valid, some folks prefer to have AVS disabled in the > system during boot for couple of reasons I know of: > a) during system boot, OMAP is busy, avs comes into play during > late_init and not early_init as it needs pm configurations, pmic setup > all other stuff to be done.. so the delay between late_init and > completion of boot is pretty minimal > b) few folks would like to start the boot without avs and enable it > from userspace applications to allow debug of issues when avs is > enabled (even if avs is enabled during that little time it is > on.. they'd want to avoid it).. > >> Some of the initial silicon revisions did not have the efuse data to >> Required for AVS. I believe AVS is disabled - by default - to ensure >> compatibility with these devices. > this should not be a problem - SR driver is smart and will look at > it's data structures and say - oh, this device does not have efuse, so > it will crib back saying - good try - but sorry, I cant enable avs at > this OPP frequency because I dont have efuse data to program the SR > AVS module.. > > > All said and done, there are configurations which enable avs by > default at boot - the corresponding variable is initialized as one in > thier private trees.. We should probably consider having the SR enable/disable default as an option availble to platform code. As part of the SR rewrite, Thara has converted this to a stadard platform_device/platform_driver model so should be easier then. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
