Re: [LinuxBIOS] [Patch] AMD cs5536 uart disable

[ron minnich]

Acked-by: Ronald G. Minnich

On 5/30/07, Marc Jones  wrote:
> The UART disable code was causing a hang and was worked around with a
> return that skipped the disable code. This patch removes the return and
> fixes the UART disable code.
>
> The problem was that the disable code was ORing bits into the Legacy_IO
> MSR causing issues with the LPC SIOs init code that would manifest as a
> hang because the IO would not be decoded correctly. ANDing to clear the
> bits fixes the issue.
>
> Signed-off-by: Marc Jones
> Index: cs5536.c
>
> --- cs5536.c    (revision 2705)
> +++ cs5536.c    (working copy)
> @@ -316,9 +316,6 @@
>     } else {
>             /* Reset and disable COM1 */
>           printk_err("Not disabling COM1 due to a bug ...\n");
>           /* for now, don't do this! */
>           return;
>           msr = rdmsr(MDD_UART1_CONF);
>           msr.lo = 1;     // reset
>           wrmsr(MDD_UART1_CONF, msr);
>
> @@ -327,7 +324,7 @@
>             /* Disable the IRQ */
>             msr = rdmsr(MDD_LEG_IO);
>           msr.lo |= ~(0xF << 16);
>           msr.lo &= ~(0xF << 16);
>           wrmsr(MDD_LEG_IO, msr);
>   }
>
> @@ -391,7 +388,7 @@
>             /* Disable the IRQ */
>             msr = rdmsr(MDD_LEG_IO);
>           msr.lo |= ~(0xF << 20);
>           msr.lo &= ~(0xF << 20);
>           wrmsr(MDD_LEG_IO, msr);
>   }
>
> }