Re: [PATCH 5/11] EHCI: fix problem with BIOS handoff

On Thursday 05 April 2007 1:06 pm, Alan Stern wrote:
> This patch (as882) fixes a problem with the EHCI BIOS handoff.  On my
> machine, the BIOS configures the controller and the handoff fails,
> leaving the controller configured.  During resume-from-disk, this
> confuses ehci-hcd into thinking that the controller has not been
> tampered with.
> 
> The problem is fixed by turning off the Configured Flag whenever a
> BIOS handoff is attempted, whether it succeeds or not.
> 
> Signed-off-by: Alan Stern <[email protected]>

Signed-off-by: David Brownell <[email protected]>


> 
> ---
> 
> Index: usb-2.6/drivers/usb/host/pci-quirks.c
> ===================================================================
> --- usb-2.6.orig/drivers/usb/host/pci-quirks.c
> +++ usb-2.6/drivers/usb/host/pci-quirks.c
> @@ -44,6 +44,7 @@
>  #define EHCI_USBSTS		4		/* status register */
>  #define EHCI_USBSTS_HALTED	(1 << 12)	/* HCHalted bit */
>  #define EHCI_USBINTR		8		/* interrupt register */
> +#define EHCI_CONFIGFLAG		0x40		/* configured flag register */
>  #define EHCI_USBLEGSUP		0		/* legacy support register */
>  #define EHCI_USBLEGSUP_BIOS	(1 << 16)	/* BIOS semaphore */
>  #define EHCI_USBLEGSUP_OS	(1 << 24)	/* OS semaphore */
> @@ -216,6 +217,7 @@ static void __devinit quirk_usb_disable_
>  	u32	hcc_params, val;
>  	u8	offset, cap_length;
>  	int	count = 256/4;
> +	int	tried_handoff = 0;
>  
>  	if (!mmio_resource_enabled(pdev, 0))
>  		return;
> @@ -273,6 +275,7 @@ static void __devinit quirk_usb_disable_
>  			 */
>  			msec = 5000;
>  			while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
> +				tried_handoff = 1;
>  				msleep(10);
>  				msec -= 10;
>  				pci_read_config_dword(pdev, offset, &cap);
> @@ -292,6 +295,12 @@ static void __devinit quirk_usb_disable_
>  			pci_write_config_dword(pdev,
>  					offset + EHCI_USBLEGCTLSTS,
>  					0);
> +
> +			/* If the BIOS ever owned the controller then we
> +			 * can't expect any power sessions to remain intact.
> +			 */
> +			if (tried_handoff)
> +				writel(0, op_reg_base + EHCI_CONFIGFLAG);
>  			break;
>  		case 0:			/* illegal reserved capability */
>  			cap = 0;
> 

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