Re: [PATCH] Re: still having r8169 woes with XID 18000000

[Eric Dumazet <eric.dumazet@gmail.com>]

Le samedi 05 juin 2010 à 10:39 +0300, Timo Teräs a écrit :

> Ok, I compared Realtek's and the in-tree driver. The only essential
> difference is that Realtek driver uses udelay(100) in mdio_write()'s
> busy polling loop where as the in-tree uses udelay(25). And that seems
> to be the magic difference! Using udelay(100) fixes this!
> 
> I'm guessing that the phy needs slight delay between consecutive
> mdio_write's even if it has advertised that the write has been
> completed. And yes, just adding a small delay in the end of mdio_write
> does seem to work too.
> 
> Francois, you think the below patch is ok? Should I send it as properly
> formatted commit?
> 
> diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
> index 217e709..6db62bf 100644
> --- a/drivers/net/r8169.c
> +++ b/drivers/net/r8169.c
> @@ -559,6 +559,7 @@ static void mdio_write(void __iomem *ioaddr,
>  			break;
>  		udelay(25);
>  	}
> +	udelay(25);
>  }
> 
>  static int mdio_read(void __iomem *ioaddr, int reg_addr)
> --

Sure this deserves an official patch with all prereqs, but please add a
comment in mdio_write() why this extra udelay(25) is needed, especially
since you say of udelay(100) 'fixes the bug'.