RE: [PATCH] [RFC] USB: EHCI: mark several functions as maybe unused

[Nguyen Dinh-R00091 <R00091@xxxxxxxxxxxxx>]

> -----Original Message-----
> From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx]
> Sent: Tuesday, October 05, 2010 9:17 AM
> To: Uwe Kleine-KÃnig
> Cc: linux-usb@xxxxxxxxxxxxxxx; Eric BÃnard; Wolfram Sang; Daniel Mack;
> Nguyen Dinh-R00091; Valentin Longchamp; Sascha Hauer
> Subject: Re: [PATCH] [RFC] USB: EHCI: mark several functions as maybe
> unused
> 
> On Tue, 5 Oct 2010, [UTF-8] Uwe Kleine-KÃÂnig wrote:
> 
> > Hello,
> >
> > I don't know much about usb drivers in general or ehci, but the
> warnings
> > below clutter our auto build logs since quite some time.
> >
> > Maybe someone can clearify if it's OK for the mxc driver not to use the
> > functions marked by my patch?!
> >
> > Best regards
> > Uwe
> >
> > --------------------- >8 ---------------------
> > - ehci_lpm_check and ehci_lpm_set_da are only used in
> ehci_update_device
> >   defined in drivers/usb/host/ehci-pci.c.
> > - ehci_adjust_port_wakeup_flags (disguised as
> >   ehci_prepare_ports_for_controller_suspend and
> >   ehci_prepare_ports_for_controller_resume),
> ehci_clear_tt_buffer_complete
> >   and ehci_endpoint_reset are used in several drivers, but not in ehci-
> mxc.c
> >
> > This fixes the following warnings:
> >
> >         drivers/usb/host/ehci-lpm.c:21: warning: 'ehci_lpm_set_da'
> defined but not used
> >         drivers/usb/host/ehci-lpm.c:41: warning: 'ehci_lpm_check'
> defined but not used
> >         drivers/usb/host/ehci-q.c:148: warning:
> 'ehci_clear_tt_buffer_complete' defined but not used
> >         drivers/usb/host/ehci-hcd.c:1088: warning:
> 'ehci_endpoint_reset' defined but not used
> >         drivers/usb/host/ehci-hub.c:111: warning:
> 'ehci_adjust_port_wakeup_flags' defined but not used
> >
> > when compiling with USB_EHCI_MXC.
> 
> I have no idea about ehci_lpm_check or ehci_lpm_set_da.  From a cursory
> inspection, it appears that this file should be included only in builds
> where it gets used (currently only in PCI).
> 
> ehci_adjust_port_wakeup_flags should be used in every driver that
> supports suspend & resume.  But since your driver doesn't, marking them
> __maybe_unused is okay.
> 
> ehci_clear_tt_buffer_complete and ehci_endpoint_reset must be used by
> every EHCI driver.  The correct fix is to add them to your driver's
> hc_driver structure.
> 
> Alan Stern
> 

Hi Uwe,
Currently our internal port of ehci is using ehci_clear_tt_buffer_complete and ehci_endpoint_reset per Alan's recommendation. I will look into adding it to the ehci-mxc hc_driver structure.

On the point of the ehci_adjust_port_wakeup_flags, I am starting to at adding suspend/resume support in the ehci_mxc driver. But until that patch is ready, the _unused_ flag is ok. My patch could remove them when it gets created.

Thanks,
Dinh

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