Re: [PATCH] vt_buffer: drop console buffer copying optimisations

[Peter Hurley]

On 01/28/2015 11:11 PM, Dave Airlie wrote:
> These two copy to/from VGA memory, however on the Silicon
> Motion SMI750 VGA card on a 64-bit system cause console corruption.
> 
> This is due to the hw being buggy and not handling a 64-bit transaction
> correctly.
> 
> We could try and create a 32-bit version of these routines,
> but I'm not sure the optimisation is worth much today.
> 
> Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1132826

Restricted link.


> Tested-by: Huawei engineering.
> Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
> ---
> 
> Linus, this came up a while back I finally got some confirmation
> that it fixes those servers.
> 
>  include/linux/vt_buffer.h | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h
> index 057db7d..f38c10b 100644
> --- a/include/linux/vt_buffer.h
> +++ b/include/linux/vt_buffer.h
> @@ -21,10 +21,6 @@
>  #ifndef VT_BUF_HAVE_RW
>  #define scr_writew(val, addr) (*(addr) = (val))
>  #define scr_readw(addr) (*(addr))
> -#define scr_memcpyw(d, s, c) memcpy(d, s, c)
> -#define scr_memmovew(d, s, c) memmove(d, s, c)
> -#define VT_BUF_HAVE_MEMCPYW
> -#define VT_BUF_HAVE_MEMMOVEW
>  #endif
>  
>  #ifndef VT_BUF_HAVE_MEMSETW
> 

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