[edk2-devel] [PATCH] MdeModulePkg/UsbBusDxe: Return error when the device is not present
Wu, Hao A
hao.a.wu at intel.com
Fri Aug 2 01:05:09 UTC 2019
> -----Original Message-----
> From: devel at edk2.groups.io [mailto:devel at edk2.groups.io] On Behalf Of
> Laszlo Ersek
> Sent: Wednesday, July 31, 2019 7:37 PM
> To: Marcin Wojtas; devel at edk2.groups.io
> Cc: leif.lindholm at linaro.org; ard.biesheuvel at linaro.org; jsd at semihalf.com;
> jaz at semihalf.com; Tian, Feng; Kinney, Michael D; Gao, Liming
> Subject: Re: [edk2-devel] [PATCH] MdeModulePkg/UsbBusDxe: Return error
> when the device is not present
>
> On 07/31/19 08:25, Marcin Wojtas wrote:
> > Until now, during the USB device enumeration when its PortState
> > USB_PORT_STAT_CONNECTION bit was not set, the stack was not
> informed
> > that the device is not present. Fix that by returning appropriate
> > error code.
> >
> > Change-Id: I588f82b987993e9755f64ce76cde9eb690ef1d54
> > Signed-off-by: Marcin Wojtas <mw at semihalf.com>
> > ---
> > MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c
> b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c
> > index be9d9bd..ab1db15 100644
> > --- a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c
> > +++ b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c
> > @@ -719,6 +719,7 @@ UsbEnumerateNewDev (
> >
> > if (!USB_BIT_IS_SET (PortState.PortStatus,
> USB_PORT_STAT_CONNECTION)) {
> > DEBUG ((EFI_D_ERROR, "UsbEnumerateNewDev: No device present at
> port %d\n", Port));
> > + Status = EFI_NOT_FOUND;
> > goto ON_ERROR;
> > } else if (USB_BIT_IS_SET (PortState.PortStatus,
> USB_PORT_STAT_SUPER_SPEED)){
> > Child->Speed = EFI_USB_SPEED_SUPER;
> >
>
> I think the patch is correct, based on a quite superficial analysis (i.e. without
> actual knowledge of USB specifics on my part).
>
> The reason is that Status is EFI_SUCCESS when the "goto" statement is
> reached, due to the preceding context
>
> Status = HubApi->GetPortStatus (HubIf, Port, &PortState);
>
> if (EFI_ERROR (Status)) {
> DEBUG ((EFI_D_ERROR, "UsbEnumerateNewDev: failed to get speed of
> port %d\n", Port));
> goto ON_ERROR;
> }
>
> And, the ON_ERROR label is documented as:
>
> ON_ERROR:
> //
> // If reach here, it means the enumeration process on a given port is
> interrupted due to error.
> // [...]
> //
> return Status;
>
> We shouldn't report success when there is no device present on the port.
>
> I think EFI_NOT_FOUND is a suitable error code; while it is not listed explicitly
> in the leading comment on the function, it does fit under
>
> @retval Others Failed to enumerate the device.
>
> Marcin, can you please remove the "Change-Id" tag from the commit
> message? (Or the MdeModulePkg maintainers could do that, just before
> they push the patch.)
Thanks Laszlo,
I will help to remove the 'Change-Id' tag when pushing this patch.
Best Regards,
Hao Wu
>
> With "Change-Id" removed:
>
> Reviewed-by: Laszlo Ersek <lersek at redhat.com>
>
> Thanks
> Laszlo
>
>
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