Hi, Felipe Ferreri Tonello <e...@felipetonello.com> writes: > [ text/plain ] > Hi Balbi, > > On March 4, 2016 7:16:42 AM GMT+00:00, Felipe Balbi <ba...@kernel.org> wrote: >> >>Hi, >> >>"Felipe F. Tonello" <e...@felipetonello.com> writes: >>> [ text/plain ] >>> This gadget uses a bmAttributes and MaxPower that requires the USB >>bus to be >>> powered from the host, which is not correct because this >>configuration is device >>> specific, not a USB-MIDI requirement. >>> >>> This patch adds two modules parameters, bmAttributes and MaxPower, >>that allows >>> the user to set those flags. The default values are what the gadget >>used to use >>> for backward compatibility. >>> >>> Signed-off-by: Felipe F. Tonello <e...@felipetonello.com> >>> --- >>> drivers/usb/gadget/legacy/gmidi.c | 14 ++++++++++++-- >>> 1 file changed, 12 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/usb/gadget/legacy/gmidi.c >>b/drivers/usb/gadget/legacy/gmidi.c >>> index fc2ac150f5ff..0553435cc360 100644 >>> --- a/drivers/usb/gadget/legacy/gmidi.c >>> +++ b/drivers/usb/gadget/legacy/gmidi.c >>> @@ -63,6 +63,14 @@ static unsigned int out_ports = 1; >>> module_param(out_ports, uint, S_IRUGO); >>> MODULE_PARM_DESC(out_ports, "Number of MIDI output ports"); >>> >>> +static unsigned int bmAttributes = USB_CONFIG_ATT_ONE; >>> +module_param(bmAttributes, uint, S_IRUGO); >>> +MODULE_PARM_DESC(bmAttributes, "Configuration Descriptor's >>bmAttributes parameter"); >>> + >>> +static unsigned int MaxPower = CONFIG_USB_GADGET_VBUS_DRAW; >>> +module_param(MaxPower, uint, S_IRUGO); >>> +MODULE_PARM_DESC(MaxPower, "Used to calculate Configuration >>Descriptor's bMaxPower parameter"); >> >>you didn't run checkpatch, did you ? Also, are you sure you will need >>to >>change this by simply reloading the module ? I'm not convinced. > > Yes I always run checkpatch :)
do you really ? Why do you have a 98-character line, then ?
> What do you mean by reloading the module?
modprobe g_midi MaxPower=4
modprobe -r g_midi
modprobe g_midi MaxPower=10
I'm not convinced this is a valid use-case. Specially since you can just
provide several configurations and let the host choose the one it suits
it best.
>>> @@ -119,8 +127,8 @@ static struct usb_configuration midi_config = {
>>> .label = "MIDI Gadget",
>>> .bConfigurationValue = 1,
>>> /* .iConfiguration = DYNAMIC */
>>> - .bmAttributes = USB_CONFIG_ATT_ONE,
>>
>>nack, nackety nack nack nack :-)
>>
>>USB_CONFIG_ATT_ONE *must* always be set. With your module parameter you
>>give users the oportunity to violate USB spec.
>
> You are right. It needs to check the value before it assigns to
> bmAttributes.
why check ? You can just unconditionally or USB_CONFIG_ATT_ONE. In any
case, I'm not convinced this is necessary at all.
--
balbi
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