On 7/3/19 1:43 PM, Michal Suchánek wrote: > On Wed, 3 Jul 2019 13:26:50 +0200 > Marek Vasut <ma...@denx.de> wrote: > >> On 7/3/19 11:46 AM, Michal Suchánek wrote: >>> On Tue, 2 Jul 2019 23:20:28 +0200 >>> Marek Vasut <ma...@denx.de> wrote: >>> >>>> On 7/2/19 9:31 PM, Michal Suchánek wrote: >>>>> On Tue, 2 Jul 2019 20:38:27 +0200 >>>>> Marek Vasut <ma...@denx.de> wrote: >>>>> >>>>>> On 7/2/19 7:50 PM, Michal Suchánek wrote: >>>>>>> On Tue, 2 Jul 2019 18:58:54 +0200 >>>>>>> Marek Vasut <ma...@denx.de> wrote: >>>>>>> >>>>>>>> On 7/2/19 4:22 PM, Michal Suchánek wrote: >>>>>>>>> On Tue, 2 Jul 2019 15:11:07 +0200 >>>>>>>>> Marek Vasut <ma...@denx.de> wrote: >>>>>>>>> >>>>>>>>>> On 7/2/19 3:04 PM, Michal Suchánek wrote: >>>>>>>>>>> On Tue, 2 Jul 2019 13:58:30 +0200 >>>>>>>>>>> Marek Vasut <ma...@denx.de> wrote: >>>>>>>>>>> >>>>>>>>>>>> On 7/1/19 5:56 PM, Michal Suchanek wrote: >>>>>>>>>>>>> Causes unbound key repeat on error otherwise. >>>>>>>>>>>>> >>>>>>>>>>>>> Signed-off-by: Michal Suchanek <msucha...@suse.de> >>>>>>>>>>>>> --- >>>>>>>>>>>>> common/usb_kbd.c | 7 +++---- >>>>>>>>>>>>> 1 file changed, 3 insertions(+), 4 deletions(-) >>>>>>>>>>>>> >>>>>>>>>>>>> diff --git a/common/usb_kbd.c b/common/usb_kbd.c >>>>>>>>>>>>> index cc99c6be0720..948f9fd68490 100644 >>>>>>>>>>>>> --- a/common/usb_kbd.c >>>>>>>>>>>>> +++ b/common/usb_kbd.c >>>>>>>>>>>>> @@ -339,10 +339,9 @@ static inline void >>>>>>>>>>>>> usb_kbd_poll_for_event(struct usb_device *dev) >>>>>>>>>>>>> struct usb_kbd_pdata *data = dev->privptr; >>>>>>>>>>>>> >>>>>>>>>>>>> /* Submit a interrupt transfer request */ >>>>>>>>>>>>> - usb_submit_int_msg(dev, data->intpipe, &data->new[0], >>>>>>>>>>>>> data->intpktsize, >>>>>>>>>>>>> - data->intinterval); >>>>>>>>>>>>> - >>>>>>>>>>>>> - usb_kbd_irq_worker(dev); >>>>>>>>>>>>> + if (!usb_submit_int_msg(dev, data->intpipe, &data->new[0], >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Shouldn't you propagate return value from this function ? It can >>>>>>>>>>>> return >>>>>>>>>>>> ENOTSUPP. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> If it did then probing keyboard would fail and we would not get >>>>>>>>>>> here. >>>>>>>>>> >>>>>>>>>> So there is no chance this function could return an error here, ever >>>>>>>>>> ? >>>>>>>>>> E.g. what if it's implemented and someone yanks the keyboard cable >>>>>>>>>> out >>>>>>>>>> just at the right time ? >>>>>>>>> >>>>>>>>> It returns errors all the time with dwc2. That's why we need to check >>>>>>>>> for the error condition. We should not get here if probing the >>>>>>>>> keyboard >>>>>>>>> failed, though. So if the function is not supported we will not get >>>>>>>>> here. Anyway, if it's not supported or the keyboard is missing it by >>>>>>>>> definition cannot provide useful result so we should not process it. >>>>>>>>> >>>>>>>> >>>>>>>> Except you start ignoring the error value from e.g. malfunctioning >>>>>>>> keyboard here, instead of propagating it, correct ? >>>>>>> >>>>>>> It was never propagated to start with. The return value was not checked >>>>>>> at all. What I do here is check the return value and not process the >>>>>>> data on error whatever it contains (like the keypress returned last >>>>>>> time valid data was received). >>>>>> >>>>>> I can see a patch which checks usb_kbd_poll_for_event() return value. >>>>>> Can you add one ? >>>>> >>>>> What for? Apparently the keypress is processed in usb_kbd_irq_worker. >>>>> So checking the return value is needed to decide if the worker should >>>>> run, and is not particularly useful outside usb_kbd_poll_for_event. We >>>>> could signal a getc() failure but do we have any code handling getc() >>>>> failures? >>>> >>>> I presume getc() might signal EOF if the underlying hardware fails. >>>> But in general, it's a good practice to not ignore errors. >>>> >>> >>> It is not such a great idea. You might have multiple input hardware (ie >>> serial and usb keyboard). What does it mean that usb keyboard failed in >>> this context? >> >> I'd say, the behavior is undefined ? > > But we need to define it which the code does by ignoring the > device-specific error and relying on devices that are still working > (like a serial port) or for which error detection is not available > (like most serial ports).
Maybe the error should still be propagated to the input layer , and not ignored at the USB layer ? >>> So in my view the ultimate consumer of getc() has no use for the error >>> so there is no point in propagating it. >> >> Ignoring errors and not reporting them isn't nice either, so what other >> option(s) do we have here ? > > Ignoring the errors is exactly the desirable behavior when facing > broken hardware like dwc2. On non-broken hardware you will get fewer > errors to ignore. It is up to the device driver to report device > failure with a message when the error condition could be informative to > the user (such as previously working device going away completely). I thought this error is a keyboard failure though , and has nothing to do with the USB controller ? [...] _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
