That looks fine.
Acked-by: Dave Jiang <dave.ji...@intel.com>
On Fri, 2013-08-02 at 09:34 +0200, Brice Goglin wrote:
> Le 01/08/2013 19:15, Jiang, Dave a écrit :
> > On Thu, 2013-08-01 at 10:11 -0700, Jon Mason wrote:
> >> On Wed, Jul 31, 2013 at 03:14:07PM -0700, Jiang, Dave wrote:
> >>> I'm ok with enabling this for people that just want to use DMA and not
> >>> RAID.
> >> I might be crazy, but I'd be in favor of disabling the RAID offload by
> >> default on non-Atom platforms.
> >>
> > I suppose. Technically it is disabled starting with 3.10 because of the
> > channel switch issue. I'm ok with this disabled by default for the 3.2
> > platforms that has broken pq-val.
> >
>
> Here's a patch that may do what you guys are saying.
>
> Brice
>
>
>
> ioatdma: disable RAID by default when buggy and add module param
>
> Commit f26df1a1 added a 64-byte alignment requirement for legacy
> operations to work around a silicon errata when mixing legacy and
> RAID descriptors.
>
> RAID offload is now disabled by default on buggy 3.2 platforms.
> Passing ioat_raid_enabled=1 force-enables it on all platforms
> (previous behavior).
> Passing ioat_raid_enabled=0 force-disables it everywhere.
>
> When RAID offload is disabled, legacy operations (memcpy, etc.)
> can work again without alignment restrictions.
>
> Signed-off-by: Brice Goglin <brice.gog...@inria.fr>
> ---
> drivers/dma/ioat/dma_v3.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> Index: b/drivers/dma/ioat/dma_v3.c
> ===================================================================
> --- a/drivers/dma/ioat/dma_v3.c 2013-07-31 23:06:24.163810000 +0200
> +++ b/drivers/dma/ioat/dma_v3.c 2013-08-02 09:28:51.817037742 +0200
> @@ -67,6 +67,11 @@
> #include "dma.h"
> #include "dma_v2.h"
>
> +static int ioat_raid_enabled = -1;
> +module_param(ioat_raid_enabled, int, 0444);
> +MODULE_PARM_DESC(ioat_raid_enabled,
> + "control support of RAID offload (-1=enabled unless broken
> [default], 0=disabled, 1=enabled)");
> +
> /* ioat hardware assumes at least two sources for raid operations */
> #define src_cnt_to_sw(x) ((x) + 2)
> #define src_cnt_to_hw(x) ((x) - 2)
> @@ -1775,7 +1780,7 @@ int ioat3_dma_probe(struct ioatdma_devic
> dma->device_alloc_chan_resources = ioat2_alloc_chan_resources;
> dma->device_free_chan_resources = ioat2_free_chan_resources;
>
> - if (is_xeon_cb32(pdev))
> + if (ioat_raid_enabled == 1 && is_xeon_cb32(pdev))
> dma->copy_align = 6;
>
> dma_cap_set(DMA_INTERRUPT, dma->cap_mask);
> @@ -1783,7 +1788,14 @@ int ioat3_dma_probe(struct ioatdma_devic
>
> device->cap = readl(device->reg_base + IOAT_DMA_CAP_OFFSET);
>
> - if (is_bwd_noraid(pdev))
> + /* disable RAID if:
> + * force-disabled by module param,
> + * or not force-enabled on buggy 3.2 platforms,
> + * or not actually supported.
> + */
> + if (ioat_raid_enabled == 0
> + || (ioat_raid_enabled != 1 && is_xeon_cb32(pdev))
> + || is_bwd_noraid(pdev))
> device->cap &= ~(IOAT_CAP_XOR | IOAT_CAP_PQ |
> IOAT_CAP_RAID16SS);
>
> /* dca is incompatible with raid operations */
>
>
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