[U-Boot] [PATCH] usb: remove unnecessary packed attributes

Lucas Stach dev at lynxeye.de
Thu Aug 30 23:42:58 CEST 2012


Dear Marek,

it seems you are right. Though it works for me this may be pure luck. So
please disregard this patch, I'll fix this up more properly.

Thanks,
Lucas

Am Donnerstag, den 30.08.2012, 22:59 +0200 schrieb Marek Vasut:
> Dear Marek Vasut,
> 
> > Dear Lucas Stach,
> > 
> > > We don't actually need to pack those structs, as they
> > > are not used to do actual hardware access.
> > > 
> > > This avoids some unaligned accesses and therefore makes
> > > the EHCI stack work on ARMv7 without compiler workarounds.
> > > 
> > > Signed-off-by: Lucas Stach <dev at lynxeye.de>
> > 
> > I need to review this properly, will get back to it soon.
> 
> My 7th sense is telling me, these descriptors are sent across the bus. 
> ehci_submit_root() puts them into buffer and then ehci_submit_async() blasts 
> them. I believe they must be packed, otherwise the format expected by devices on 
> the bus won't match and it'll fall apart.
> 
> > Until then, CCing other good fellows.
> > 
> > > ---
> > > 
> > >  drivers/usb/host/ehci-hcd.c | 2 +-
> > >  include/usb.h               | 2 +-
> > >  2 Dateien geändert, 2 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-)
> > > 
> > > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> > > index 18b4bc6..2f4fa5e 100644
> > > --- a/drivers/usb/host/ehci-hcd.c
> > > +++ b/drivers/usb/host/ehci-hcd.c
> > > @@ -45,7 +45,7 @@ static struct descriptor {
> > > 
> > >  	struct usb_linux_config_descriptor config;
> > >  	struct usb_linux_interface_descriptor interface;
> > >  	struct usb_endpoint_descriptor endpoint;
> > > 
> > > -}  __attribute__ ((packed)) descriptor = {
> > > +} descriptor = {
> > > 
> > >  	{
> > >  	
> > >  		0x8,		/* bDescLength */
> > >  		0x29,		/* bDescriptorType: hub descriptor */
> > > 
> > > diff --git a/include/usb.h b/include/usb.h
> > > index ba3d169..63730ee 100644
> > > --- a/include/usb.h
> > > +++ b/include/usb.h
> > > @@ -369,7 +369,7 @@ struct usb_hub_descriptor {
> > > 
> > >  	unsigned char  PortPowerCtrlMask[(USB_MAXCHILDREN+1+7)/8];
> > >  	/* DeviceRemovable and PortPwrCtrlMask want to be variable-length
> > >  	
> > >  	   bitmaps that hold max 255 entries. (bit0 is ignored) */
> > > 
> > > -} __attribute__ ((packed));
> > > +};
> > > 
> > >  struct usb_hub_device {
> > 
> > Best regards,
> > Marek Vasut
> 
> Best regards,
> Marek Vasut
> 




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