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

Marek Vasut
2012-08-30T21:56:48Z

Dear Lucas Stach,

> 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.

Cool thing we caught it :-)

http://www.denx.de/wiki/U-Boot/Patches btw read up here ... don't top-post ...
you know the drill.

> 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@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 ge?ndert, 2 Zeilen hinzugef?gt(+), 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

Best regards,
Marek Vasut