>>-----Original Message----- >>From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >>Sent: Tuesday, November 16, 2010 3:43 AM >>To: Gopinath, Thara >>Cc: linux-omap@xxxxxxxxxxxxxxx; paul@xxxxxxxxx; Cousson, Benoit; Sripathy, >>Vishwanath; Sawant, Anand >>Subject: Re: [PATCH v4 7/9] OMAP3: PM: Adding debug support to Voltage and >>Smartreflex drivers >> >>"Gopinath, Thara" <thara@xxxxxx> writes: >> >>>>>-----Original Message----- >>>>>From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >>>>>Sent: Thursday, November 11, 2010 12:43 AM >>>>>To: Gopinath, Thara >>>>>Cc: linux-omap@xxxxxxxxxxxxxxx; paul@xxxxxxxxx; Cousson, Benoit; Sripathy, >>>>>Vishwanath; Sawant, Anand >>>>>Subject: Re: [PATCH v4 7/9] OMAP3: PM: Adding debug support to Voltage and >>>>>Smartreflex drivers >>>>> >>>>>Thara Gopinath <thara@xxxxxx> writes: >>>>> >>>>>> This patch adds debug support to the voltage and smartreflex drivers. >>>>>> This means a whole bunch of voltage processor and smartreflex >>>>>> parameters are now visible through the pm debugfs. >>>>>> The voltage parameters can be viewed at >>>>>> /debug/voltage/vdd_<x>/<parameter> >>>>>> and the smartreflex parameters can be viewed at >>>>>> /debug/vdd_<x>/smartreflex/<parameter> >>>>>> >>>>>> To enable overriding of these parameters from user side, write 1 >>>>>> into >>>>>> /debug/voltage/vdd_<x>/override_volt_params >>>>> >>>>>Please just git rid of any sort of override parameter from sysfs. >>>>> >>>>>Instead, you can detect in the sysfs code itself if any parameters were >>>>>changed and then set the vdd->user_override flag. But in the sys-fs code I do not have access to vdd. How do I then set this flag? >>> >>> But when will I unset this flag?? >> >>You can't. >> >>And, AFAICT, it wasn't clear from the current code or docs whether this >>could work or was expected to work either, e.g., if you set >>override_volt_params back to zero, to the original values all get reused? >> >>If you want to provide this feature, then it should be documented and >>made clear that this is an intended goal. >> >>Thinking about this more, the main thing I don't like about this >>approach is that the active code paths (enable & disable) have to check >>each time if any of these values have been overidden. >> >>Rather than have several places in the active code paths where this >>override value is checked, there the sysfs methods should simply update >>the values that are used by the core code. This way, the core would >>not need to know about where the values came from (defalts, volt_data, >>user override, etc.) >> >>If you want to provide a way to revert this, then maybe writing -1 will >>should switch that value back to the HW default, or volt_data default. Kevin, Benoit, Nishant et al, Without this override flag today there is no direct way of allowing user to write into these parameters. My question is, is there a need for the parameters to be over-written from the user-space? If yes, I need ideas on how to implement it with using override_volt_params ! Regards Thara -- 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
