Re: [Qemu-devel] enabling bus-master IDE driver

[Jason Brittain <jason@brittainweb.org>]

I just pulled the latest source from CVS (today's), and tried
looking at DMA again.

Host: Linux 2.6 (Fedora Core 2)
Guest: XP corp.
It still says the primary IDE channel is in PIO mode, and
doesn't seem any faster.

Host: Linux 2.6 (Fedora Core 2)
Guest: Linux 2.6
hdparm now reports that DMA is on for /dev/hda, and I can also
turn it on and off.  With it on, it's about twice as fast as
it is with it off.  So, this seems to work.

Cheers.

-- 
Jason Brittain


Jens Axboe wrote:
> On Sun, Nov 07 2004, Hetz Ben Hamo wrote:
> 
>>>>>-    put_le16(p + 49, 1 << 9); /* LBA supported, no DMA */
>>>>>+    put_le16(p + 49, 1 << 9 | 1 << 8); /* DMA and LBA supported */
>>
>>Care to put all the changes in 1 patch please, so I can put it on my web site?
> 
> 
> Here you go.
> 
> Index: hw/ide.c
> ===================================================================
> RCS file: /cvsroot/qemu/qemu/hw/ide.c,v
> retrieving revision 1.28
> diff -u -r1.28 ide.c
> --- hw/ide.c	9 Oct 2004 20:27:55 -0000	1.28
> +++ hw/ide.c	7 Nov 2004 11:19:52 -0000
> @@ -416,10 +416,10 @@
>      put_le16(p + 47, 0x8000 | MAX_MULT_SECTORS);
>  #endif
>      put_le16(p + 48, 1); /* dword I/O */
> -    put_le16(p + 49, 1 << 9); /* LBA supported, no DMA */
> +    put_le16(p + 49, 1 << 9 | 1 << 8); /* DMA and LBA supported */
>      put_le16(p + 51, 0x200); /* PIO transfer cycle */
>      put_le16(p + 52, 0x200); /* DMA transfer cycle */
> -    put_le16(p + 53, 1); /* words 54-58 are valid */
> +    put_le16(p + 53, 1 | 1 << 2); /* words 54-58,88 are valid */
>      put_le16(p + 54, s->cylinders);
>      put_le16(p + 55, s->heads);
>      put_le16(p + 56, s->sectors);
> @@ -437,6 +437,8 @@
>      put_le16(p + 85, (1 << 14));
>      put_le16(p + 86, 0);
>      put_le16(p + 87, (1 << 14));
> +    put_le16(p + 88, 0x1f | (1 << 13));
> +    put_le16(p + 93, 1 | (1 << 14) | 0x2000 | 0x4000);
>  }
>  
>  static void ide_atapi_identify(IDEState *s)
> @@ -1560,7 +1562,7 @@
>              case 0x82: /* write cache disable */
>              case 0xaa: /* read look-ahead enable */
>              case 0x55: /* read look-ahead disable */
> -                s->status = READY_STAT;
> +                s->status = READY_STAT | SEEK_STAT;
>                  ide_set_irq(s);
>                  break;
>              default:
>