[Gta04-owner] Further 3.17 kernel development for GTA04
NeilBrown
neilb at suse.de
Tue Nov 4 20:55:28 CET 2014
On Tue, 4 Nov 2014 06:54:33 +0100 "Dr. H. Nikolaus Schaller"
<hns at goldelico.com> wrote:
>
> Am 03.11.2014 um 22:50 schrieb NeilBrown <neilb at suse.de>:
>
> > On Mon, 3 Nov 2014 22:25:46 +0100 "Dr. H. Nikolaus Schaller"
> > <hns at goldelico.com> wrote:
> >
> >> Hi again,
> >>
> >> Am 03.11.2014 um 20:04 schrieb Dr. H. Nikolaus Schaller <hns at goldelico.com>:
> >>
> >>> Hi Neil,
> >>>
> >>> Am 03.11.2014 um 14:44 schrieb Dr. H. Nikolaus Schaller <hns at goldelico.com>:
> >>>
> >>>> Hi Neil,
> >>>>
> >>>> Am 03.11.2014 um 08:36 schrieb Dr. H. Nikolaus Schaller <hns at goldelico.com>:
> >>>>
> >>>>>
> >>>>> Am 03.11.2014 um 08:27 schrieb NeilBrown <neilb at suse.de>:
> >>>>>
> >>>>>> On Mon, 3 Nov 2014 07:57:00 +0100 "Dr. H. Nikolaus Schaller"
> >>>>>> <hns at goldelico.com> wrote:
> >>>>>>
> >>>>>>>
> >>>>>>> Am 03.11.2014 um 07:44 schrieb NeilBrown <neilb at suse.de>:
> >>>>>>>
> >>>>>>>> On Mon, 3 Nov 2014 07:00:42 +0100 "Dr. H. Nikolaus Schaller"
> >>>>>>>> <hns at goldelico.com> wrote:
> >>>>>>>>
> >>>>>>>>> Hi,
> >>>>>>>>>
> >>>>>>>>> Am 02.11.2014 um 10:51 schrieb NeilBrown <neilb at suse.de>:
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> I've made some useful progress.
> >>>>>>>>>>
> >>>>>>>>>> Nearly all the things that I need regularly work. So I can make phone calls
> >>>>>>>>>> (on the GTA04a4, not on the a3),
> >>>>>>>>>
> >>>>>>>>> ah, did you solve the ALSA sound driver issues?
> >>>>>>>>
> >>>>>>>> What ALSA sound driver issues?
> >>>>>>>
> >>>>>>> Proper device tree based Tri-State control for McBSP to switch between hardware and
> >>>>>>> software routing.
> >>>>>>>
> >>>>>>> http://projects.goldelico.com/p/gta04-kernel/issues/587/
> >>>>>>>
> >>>>>>> And, I had to disable something because I got kernel panics.
> >>>>>>>
> >>>>>>> Which sound system did you use? ti,omap-twl4030 or goldelico,gta04-audio?
> >>>>>>
> >>>>>> I don't have the goldelico one at all. Just ti,omap-twl4030 with some
> >>>>>> modification to support an external device connected to the voice port.
> >>>>>>
> >>>>>>
> >>>>>>>
> >>>>>>> The first one should work out of the box and the second one fails.
> >>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> use the wifi, charge the battery and
> >>>>>>>>>> monitor its status, and turn the GPS on/off using my new approach. There is
> >>>>>>>>>> no-longer an ‘rfkill' for GPS - opening /dev/ttyO1 does all that is needed.
> >>>>>>>>>
> >>>>>>>>> Hm. I am not happy that there is no rfkill. Well, someone commented that
> >>>>>>>>> GPS is not a transmitter, but Linux provides the rfkill gps switch (and we have
> >>>>>>>>> not introduced it). And, basically the antenna amplifier might transmit (if it runs
> >>>>>>>>> out of control) so it is safer in an airplane situation to be able to turn off the
> >>>>>>>>> LNA power explicitly. But keep gpsd and tangogps running. A user might
> >>>>>>>>> be just looking into local maps.
> >>>>>>>>
> >>>>>>>> It can be added back if it is really needed.
> >>>>>>>> It always thought it was a bit odd as rfkill is, like you say, primarily
> >>>>>>>> about transmitters.
> >>>>>>>>
> >>>>>>>> I'd like to know if anyone else is using a 'gps' rfkill ... I couldn't find
> >>>>>>>> any documentation or useful references last time I looked.
> >>>>>>>
> >>>>>>> I don’t know either, but that nobody might have to solve the same problem
> >>>>>>> as we have to solve.
> >>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> I'm not entirely happy with this code yet but it is quite usable.
> >>>>>>>>>>
> >>>>>>>>>> Suspend seems to work reliably, but power usage is way too high - about
> >>>>>>>>>> 50mA. There are hints in some patches in 3.18-rc, so USB might be to blame
> >>>>>>>>>> for some of that extra usage, so I'll probably be looking that that when I
> >>>>>>>>>> next get some time.
> >>>>>>>>>>
> >>>>>>>>>> My kernel doesn't currently "export" the various GPIOs that need to be
> >>>>>>>>>> manually poked.
> >>>>>>>>>> I have this code:
> >>>>>>>>>>
> >>>>>>>>>> for l in 186,high 175,high 23,low 21,high
> >>>>>>>>>> do
> >>>>>>>>>> g=${l%,*}
> >>>>>>>>>> echo $g > /sys/class/gpio/export
> >>>>>>>>>> echo ${l#*,} > /sys/class/gpio/gpio$g/direction
> >>>>>>>>>> done
> >>>>>>>>>>
> >>>>>>>>>> in an init.d script which sets some of these up. GPIO186 is particularly
> >>>>>>>>>> needed for turning the GSM modem on.
> >>>>>>>>>
> >>>>>>>>> What are these gpios good for? The modem should be controlled through
> >>>>>>>>> rfkill wwan. For this we have prepared a special driver in the gta04-kernel that
> >>>>>>>>> pulses the modem gpio in a similar way as for GPS (there is no UART we can
> >>>>>>>>> use to auto-control modem power).
> >>>>>>>>
> >>>>>>>> A driver which I obviously don't have. I'll try to look at it when I get a
> >>>>>>>> chance.
> >>>>>>>> My user-space code wants to poke the gpio, so I provided it.
> >>>>>>>> The others I just provided to I could be certain they were in the correct
> >>>>>>>> position for low power usage.
> >>>>>>>>
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> I've re-organised my tree as a set of topic branch, mostly based on
> >>>>>>>>>> v3.17, though the 'dts' branch with device-tree changes is based on
> >>>>>>>>>>
> >>>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap
> >>>>>>>>>> tag omap-for-v3.17/dt-gta04
> >>>>>>>>>> which has some gta04 stuff that didn't quite make 3.17 - is in 3.18-rc1
> >>>>>>>>>>
> >>>>>>>>>> The branches are:
> >>>>>>>>>>
> >>>>>>>>>> 'dts', 'hdq', 'dss', 'pwm-old', 'input', 'hacks', 'wifi', 'extcon', 'itg',
> >>>>>>>>>> ‘tty-slave', 'audio', 'twl4030' and 'charger'
> >>>>>>>>>
> >>>>>>>>> the hdq patch (there is a missing/wrong compatible entry in the driver)
> >>>>>>>>> appears to be the last missing piece we have to make it working .
> >>>>>>>>>
> >>>>>>>>> Does it work for you? I see it start up and read the bq27000 several times,
> >>>>>>>>> but ca. 4.5 seconds after kernel startup it stops. I suspect some IRQ
> >>>>>>>>> interference (maybe from a subsystem that you do not have).
> >>>>>>>>
> >>>>>>>> It works very reliably for me.
> >>>>>>>> The behaviour you describe is vaguely reminiscent of problems I was having
> >>>>>>>> ages ago which were due to runtime PM issues with the hdq driver. I think
> >>>>>>>> the fixes went upstream, possibly
> >>>>>>>> commit c354a86484b61e32100eb94c1f3f0aa512958cee
> >>>>>>>>
> >>>>>>>> Looking at my mail records, the issue was fixed in 3.6.
> >>>>>>>>
> >>>>>>>> There was one time recently when reads from one of the sysfs bq27000 files started
> >>>>>>>> returning ENXIO (or maybe ENODEV), but it hasn't happened again. I'll keep an eye
> >>>>>>>> out for problems.
> >>>>>>>
> >>>>>>> It is indeed strange. I have added some printk to report hdq write&read and timeouts:
> >>>>>>>
> >>>>>>> [ 3.894470] omapfb omapfb: no displays
> >>>>>>> [ 3.899444] omapfb omapfb: failed to setup omapfb
> >>>>>>> [ 3.904449] platform omapfb: Driver omapfb requests probe deferral
> >>>>>>> [ 3.912017] platform 4806a000.serial: Driver omap_uart requests probe deferral
> >>>>>>> [ 3.920532] platform 4806c000.serial: Driver omap_uart requests probe deferral
> >>>>>>> [ 3.929016] platform 480b4000.mmc: Driver omap_hsmmc requests probe deferral
> >>>>>>> [ 3.938201] ALSA device list:
> >>>>>>> [ 3.941314] No soundcards found.
> >>>>>>> [ 3.947357] hdq_write_byte(00000027) ok
> >>>>>>> [ 3.951568] hdq_read_byte -> 00
> >>>>>>> [ 4.148071] hdq_write_byte timeout
> >>>>>>> [ 4.350708] hdq_read_byte timeout
> >>>>>>> [ 4.548431] hdq_write_byte timeout
> >>>>>>> [ 4.748565] hdq_read_byte timeout
> >>>>>>> [ 4.948394] hdq_write_byte timeout
> >>>>>>>
> >>>>>>> I suspect some other subsystem might be influencing interrupts.
> >>>>>>>
> >>>>>>> Something to locate by disabling one driver after the other…
> >>>>>>
> >>>>>> Can't explain that. Both my A3 and A4 boards work.
> >>>>>> Maybe watch ‘grep hdq /proc/interrupts' and see if it changes at all.
> >>>>>
> >>>>> It says :
> >>>>>
> >>>>> 235: 22 INTC 58 omap_hdq
> >>>>>
> >>>>> and does not change if I try to cat /sys/class/power_supply/bq27000-battery/voltage_now
> >>>>>
> >>>>> So indeed someone is blocking these interrupts. Now I have to identify that “someone” first,
> >>>>> but it is easier with a good test case.
> >>>>
> >>>> Looks as if I have found it, although I have really no explanation.
> >>>>
> >>>> It appears to be related to the DTR patch to omap-serial.c that we have (I think inherited from
> >>>> kernel 3.7) to control the virtual GPIO of the w2sg driver. If I checkout the latest from linus/3.18-rc2, hdq works.
> >>>>
> >>>> Of course GPS does not work any more, because the DTR control is then missing.
> >>>>
> >>>> It appears to be sufficient to add/remove that patch (which is not in mainline Linux - just in
> >>>> our 3.18-rc2 and therefore you have no chance to see this effect) to start/stop HDQ interrupts.
> >>>>
> >>>> I will report if I get a better understanding why this DTR code can interfere with HDQ and
> >>>> which line(s) of code makes the difference.
> >>>
> >>> After a lot of trial and error, I still don’t understand it. But it appears to have something to do
> >>> with the UART3 + console handling. There is one line in the driver where the DTR gpio is derived
> >>> from the device tree.
> >>>
> >>> If I keep it as is (it reads the “dtr-gpio” property from the DT), we have serial and GPS, but the hdq hangup.
> >>> If I force this gpio to 0, hdq works, but the console output goes to the LCD (I have never seen that before), and we have no GPS.
> >>> If I force it to -ENOENT (which is equivalent to a DT definition with missing dtr-gpio specification), we have serial and hdq, but no GPS.
> >>> If I force it to -EPROBE_DEFER, console goes to LCD. There is no GPS, hdq does not work.
> >>>
> >>> Now, I guess our DTR patch interferes with the takeover of UART3 by this driver. Or alternatively,
> >>> that deferred probing in omap_serial has some side-effect for UART0 or UART1.
> >>
> >> after some more tests I am quite sure that the problem is deferred probing of uart drivers.
> >>
> >> If I disable the return -EPROBE_DEFER paths [2] in serial_omap_probe() hdq works (and GPS fails).
> >> If I enable them, hdq fails and GPS works (if configured).
> >
> > Based on that evidence, it could be that the GPS interferes with HDQ.
>
> it is definitively not the GPS driver. I can disable it from .config and hdq still breaks. It is
> sufficient to have it in the DT.
>
> The only condition is that the dtr-gpio defined for the UART does not successfully probe
> immediately.
>
I decided to try your kernel
Specifically, commit 16243938d0438c872c1da06183af726631402f24 from
goldelico/work/hns/3.18-hdq, with
{ .compatible = "ti,omap-hdq", },
changed to
{ .compatible = "ti,omap3-1w", },
and the HDQ deivce sees to work perfectly. Maybe there are differences
in .config...
If you would like to give me your .config and a git commit number that is
failing for you, I'll see if I can reproduce it.
Thanks,
NeilBrown
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