On 7/3/19 6:41 PM, Michal Suchánek wrote: > On Wed, 3 Jul 2019 13:48:00 +0200 > Marek Vasut <ma...@denx.de> wrote: > >> 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 ? > > Maybe. I would leave the discussion of handling errors in the input > layer for a separate patchset.
It's literally 3-line change to make usb_kbd_poll_for_event() return the error code. >>>>> 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 ? > > As far as I know the keyboard is working fine but the controller is > failing to deliver some messages. Uh, would you be willing to debug that ? [...] _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
