Re: [PATCH 13/18] MdeModulePkg/Usb/Keyboard.c: don't request protocol before setting

["Wu, Hao A" <hao.a.wu@intel.com>]

Hello,

Inline comments below:


> -----Original Message-----
> From: Sean Rhodes <sean@starlabs.systems>
> Sent: Friday, February 11, 2022 5:27 AM
> To: devel@edk2.groups.io
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Matt DeVillier
> <matt.devillier@gmail.com>; Patrick Rudolph
> <patrick.rudolph@9elements.com>
> Subject: [PATCH 13/18] MdeModulePkg/Usb/Keyboard.c: don't request
> protocol before setting
> 
> From: Matt DeVillier <matt.devillier@gmail.com>
> 
> No need to check the interface protocol then conditionally setting,
> just set it to BOOT_PROTOCOL and check for error.
> 
> This is what Linux does for HID devices as some don't follow the USB spec.
> One example is the Aspeed BMC HID keyboard device, which adds a massive
> boot delay without this patch as it doesn't respond to 'GetProtocolRequest'.
> 
> Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> ---
>  MdeModulePkg/Bus/Usb/UsbKbDxe/KeyBoard.c | 22
> +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/MdeModulePkg/Bus/Usb/UsbKbDxe/KeyBoard.c
> b/MdeModulePkg/Bus/Usb/UsbKbDxe/KeyBoard.c
> index 5a94a4dda7..56d249f937 100644
> --- a/MdeModulePkg/Bus/Usb/UsbKbDxe/KeyBoard.c
> +++ b/MdeModulePkg/Bus/Usb/UsbKbDxe/KeyBoard.c
> @@ -863,12 +863,24 @@ InitUSBKeyboard (
>    // Set boot protocol for the USB Keyboard.
> 
>    // This driver only supports boot protocol.
> 
>    //
> 
> -  if (Protocol != BOOT_PROTOCOL) {
> 
> -    UsbSetProtocolRequest (
> 
> -      UsbKeyboardDevice->UsbIo,
> 
> -      UsbKeyboardDevice->InterfaceDescriptor.InterfaceNumber,
> 
> -      BOOT_PROTOCOL
> 
> +  Status = UsbSetProtocolRequest (
> 
> +             UsbKeyboardDevice->UsbIo,
> 
> +             UsbKeyboardDevice->InterfaceDescriptor.InterfaceNumber,
> 
> +             BOOT_PROTOCOL
> 
> +             );
> 
> +  if (EFI_ERROR (Status)) {
> 
> +    //
> 
> +    // If protocol could not be set here, it means
> 
> +    // the keyboard interface has some errors and could
> 
> +    // not be initialized
> 
> +    //
> 
> +    REPORT_STATUS_CODE_WITH_DEVICE_PATH (
> 
> +      EFI_ERROR_CODE | EFI_ERROR_MINOR,
> 
> +      (EFI_PERIPHERAL_KEYBOARD | EFI_P_EC_INTERFACE_ERROR),
> 
> +      UsbKeyboardDevice->DevicePath
> 
>        );
> 
> +
> 
> +    return EFI_DEVICE_ERROR;
> 
>    }


Sorry for a question, I do not understand why the proposed change will eliminate the boot delay.
For device that does not respond to GetProtocolRequest(), the origin flow is like:
a.1 Timeout occurs for GetProtocolRequest()
a.2 Conditionally execute UsbSetProtocolRequest()

The proposed new flow is like:
b.1 Timeout occurs for GetProtocolRequest()
b.2 Always execute UsbSetProtocolRequest()

Could you help to elaborate on the change? Thanks in advance.

Best Regards,
Hao Wu


> 
> 
> 
>    UsbKeyboardDevice->CtrlOn    = FALSE;
> 
> --
> 2.32.0