Hi, On 10/24/22 16:36, Arvid Norlander wrote: > Hi, > > I have been unable to work on this for the past few weeks, first I got > sick, then I had lots of other things I was behind on because of the > sickness, then my main computer that I develop on (not the toshiba) broke, > and got a motherboard replacement (under warranty), but then the > refurbished replacement was faulty in a different way, and I'm currently > waiting for replacement of that one. Plus I now have a lot of deadlines > that I'm behind on because of that. Ugh, I hope that things get better from here on. > In summary: I have no idea when I will have time to look at the Toshiba > again. I *do* want to get back to it eventually, but don't hold your breath. I completely understand, thank you for your contributions and so far and there is absolutely not reason to hurry with further contributions. > I do agree with your letter below though, once I get to that stuff. I have > added some comments. Sounds good. Regards, Hans > > On 2022-10-24 13:23, Hans de Goede wrote: >> Hi Arvid, >> >> On 10/7/22 14:51, Arvid Norlander wrote: >>> On 2022-10-07 13:22, Hans de Goede wrote: >>>> Hi Arvid, >>>> >>>> On 10/6/22 23:12, Arvid Norlander wrote: >>>>> Hi Hans, >>>>> >>>>> Two things: >>>>> * I have discovered that reading the fan RPM in toshiba_acpi is slow, >>>>> around 50 ms. I didn't notice it at first, but after adding some more >>>>> sensors I found (current and voltage for AC and battery) it started to >>>>> make running "sensors" visibly slow. >>>>> >>>>> I don't know what proper fix to this would be. Feel free to revert the >>>>> fan RPM for now if it is not acceptable for reading sensors to block for >>>>> ~50 ms (as opposed to the 100s of micro-seconds that other sensors such >>>>> as coretemp and acpitz take to read on that laptop). >>>> >>>> Hmm, so apparently the single ACPI call this ends up making takes along time. >>>> >>>> I wonder what happens with the CPU load if you cat the file from >>>> a "while true; do cat /sys/class/hwmon/...; done" loop in the shell. >>>> >>>> With some luck most of that 50 ms is sleeping, so we won't see say >>>> 25% load on a quad core CPU (so 100% load on 1 core) in "top". >>> >>> After testing, thankfully it seems to be the case that it is mostly >>> sleeping! >> >> That is good, still unfortunate that it takes so long though. >> >>> >>>> >>>> Regardless we also want any desktop-environment sensor applets which >>>> poll more then once/second to block on this all the time. What most hwmon >>>> drivers with slow HW access do is update the readings once per second >>>> and then return cached values for a second see e.g. : >>>> >>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/hwmon/f71882fg.c >>>> >>>> and then specifically the "bool valid;" and "unsigned long last_updated; /* In jiffies */" >>>> members of "struct f71882fg_data" and how those are used. >>>> >>>> I believe that keeping the fan rpm reading, which IMHO is the most >>>> useful one is fine when adding the caching; or alternatively you >>>> can submit a revert. >>> >>> I will try to look into this, hopefully this weekend, though I'm currently >>> down with a nasty cold, so I can't promise anything. >>> >>>> As for the AC + bat voltage/current can those be / are those retreived >>>> with the same tci_raw() call or do those require separate calls ? >>>> And if they require separate calls do those calls also all take 50 ms? >>> >>> These are separate: A shared one for AC current and AC voltage, and two >>> separate ones for battery current and battery voltage. There is also >>> more data in the AC reply one that I can't quite decode, but it seems to >>> be thermally related (but I have not managed to decode it as a temperature >>> that matches anything else). Annoyingly the windows software displays >>> almost everything in percentages on dial gauges without any units or even >>> scales, making actually figuring out the interpretations rather difficult >>> at times. >>> >>> For reading the power a call is can be issued to set the time resolution, >>> in powers of two between 1 and 16 (i.e. 1, 2, 4, 8 and 16 are valid values), >>> where 1 is slightly more than one new reading per second, while 16 is about >>> one reading every 20ish seconds. >>> >>> This suggests that the EC would be updating some periodic registers >>> internally and we are just querying them, however, these are still just as >>> slow to read as the fan. >> >> Hmm, I'm not sure what is the best thing to do here, if we end up making >> 4 calls of each 50 ms here, then that is going to block the caller for >> 200 ms which I guess might be just acceptable if we do it only once >> per x seconds, for some value of x... >> >> I guess you could use power_supply_is_system_supplied() to skip >> the AC readings when not charging, but that ends up calling _PSR >> on the ACPI AC device, which might also be slow. > > Is that what provides the value to /sys/class/power_supply/ADP1/online ? > Because that appears to be quite fast. > > I have since discovered that there seems to be another way to read these > (and some other) values that the Windows software uses sometimes, which I > *believe* to be basically a an async request and poll for completion > approach. However these calls do not appear to be that much faster when I > try them, so I'm having trouble seeing the point of it (maybe it makes more > difference on some other model?). Finally it doesn't fit the Linux HWMON > API, which is a blocking read API. > > The traces basically look like: > 1. Please load value -> OK > 2. Is it done yet? -> No > 3. Is it done yet? -> Yes, here is the value. > > Though usually it is done by point 2 already. > > The API itself for this is rather strange, my best guess is: > > {HCI_GET, async_register_id, normal_param1, normal_param2, > normal_register_id, flag for load/check for completion} > > There are several such async register IDs (0xa1, 0xa7, 0xa8, ...), but each > async register only accepts a (sometimes overlapping) subset of normal > registers. > > In summary it seems quite painful to use, for very little gain given that > the userspace API is blocking anyway. Thus I did not spend a large amount > of time on figuring out or documenting the details of this feature. I know > enough now to figure out how to do the equivilent non-async call when I see > async calls in the traces. > >> >> >>> >>>> >>>> The battery values should already be available in some form under >>>> /sys/class/power_supply/BAT* although you may only have the >>>> multiplied value of the 2 there in the form of energy_now. >>> >>> I do seem to have voltage_now and power_now. So current could be computed >>> by measuring the delta of energy_now over time and then using the voltage >>> to compute the current. >>> >>> However, the voltage as reported in /sys/class/power_supply/BAT1 does not >>> quite match the voltage I get from the HCI calls. The HCI call consistently >>> reads higher, but how much higher depends on if the AC is connected or not. >>> Also voltage_now seems to update rather more slowly than the HCI calls. >>> >>>> >>>> And the AC values are nice to have but not super interesting, >>>> so if they require another slow tci_raw() call then I'm not sure >>>> if they are worth adding. >>> >>> Yes they are slow, but they might be interesting in order to compute >>> system power usage while on AC (AC power - battery power) as it reports >>> the battery charging current while charging and the discharging current >>> while discharging. >>> >>> At the very least I will be documenting them when I get time. >> >> Yes that sounds like a good idea. I guess you could also add support >> for them in the driver, but then maybe activated with some "extended_hwmon" >> kernel-module option. Which then should default to off I guess? > > That seems like a good idea. > >> >> Regards, >> >> Hans >> > > Best regards, > Arvid Norlander >
