Subject: Re: [PATCH 3/3] 8250: add workaround for MPC8[356]xx UART break IRQ storm

From: Scott Wood <[email-masked]>
Date: Thu, 1 Dec 2011 17:51:00 -0600

On 12/01/2011 05:47 PM, Paul Gortmaker wrote:
> diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
> index 8c660af..b0f4042 100644
> --- a/include/linux/serial_8250.h
> +++ b/include/linux/serial_8250.h
> @@ -18,6 +18,11 @@
>  #define UART_BUG_TXEN	(1 << 1)	/* buggy TX IIR status */
>  #define UART_BUG_NOMSR	(1 << 2)	/* buggy MSR status bits (Au1x00) */
>  #define UART_BUG_THRE	(1 << 3)	/* buggy THRE reassertion */
> +#ifdef CONFIG_PPC32
> +#define UART_BUG_FSLBK	(1 << 4)	/* buggy FSL break IRQ storm */
> +#else	/* help GCC optimize away IRQ handler errata code for ARCH != PPC32 */
> +#define UART_BUG_FSLBK	0
> +#endif

I believe this bug still exists on our 64-bit chips.

-Scott