* [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate
@ 2016-11-10 14:51 Andy Shevchenko
2016-11-10 14:59 ` Mika Westerberg
0 siblings, 1 reply; 4+ messages in thread
From: Andy Shevchenko @ 2016-11-10 14:51 UTC (permalink / raw)
To: Lee Jones, linux-kernel, Mika Westerberg; +Cc: Andy Shevchenko
Enable MWI mechanism if PCI bus master supports it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/mfd/intel-lpss-pci.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
index 50e78db..4756153 100644
--- a/drivers/mfd/intel-lpss-pci.c
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -41,6 +41,7 @@ static int intel_lpss_pci_probe(struct pci_dev *pdev,
/* Probably it is enough to set this for iDMA capable devices only */
pci_set_master(pdev);
+ pci_try_set_mwi(pdev);
ret = intel_lpss_probe(&pdev->dev, info);
if (ret)
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate
2016-11-10 14:51 [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate Andy Shevchenko
@ 2016-11-10 14:59 ` Mika Westerberg
2016-11-10 15:22 ` Andy Shevchenko
0 siblings, 1 reply; 4+ messages in thread
From: Mika Westerberg @ 2016-11-10 14:59 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: Lee Jones, linux-kernel
On Thu, Nov 10, 2016 at 04:51:42PM +0200, Andy Shevchenko wrote:
> Enable MWI mechanism if PCI bus master supports it.
Why?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate
2016-11-10 14:59 ` Mika Westerberg
@ 2016-11-10 15:22 ` Andy Shevchenko
2016-11-10 16:39 ` Mika Westerberg
0 siblings, 1 reply; 4+ messages in thread
From: Andy Shevchenko @ 2016-11-10 15:22 UTC (permalink / raw)
To: Mika Westerberg; +Cc: Lee Jones, linux-kernel
On Thu, 2016-11-10 at 16:59 +0200, Mika Westerberg wrote:
> On Thu, Nov 10, 2016 at 04:51:42PM +0200, Andy Shevchenko wrote:
> > Enable MWI mechanism if PCI bus master supports it.
>
> Why?
It might be potential benefit in some cases. Documentation says that
standard Memory Write might supply more current data than in the CPU
modified cache line and "trashing a line in the cache may trash some
data that is more current that in the memory line". This allows to avoid
potential retries and other performance degradation issues on the bus.
Though, I dunno how to measure it.
Would be enough to extend commit message by this paragraph?
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate
2016-11-10 15:22 ` Andy Shevchenko
@ 2016-11-10 16:39 ` Mika Westerberg
0 siblings, 0 replies; 4+ messages in thread
From: Mika Westerberg @ 2016-11-10 16:39 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: Lee Jones, linux-kernel
On Thu, Nov 10, 2016 at 05:22:40PM +0200, Andy Shevchenko wrote:
> On Thu, 2016-11-10 at 16:59 +0200, Mika Westerberg wrote:
> > On Thu, Nov 10, 2016 at 04:51:42PM +0200, Andy Shevchenko wrote:
> > > Enable MWI mechanism if PCI bus master supports it.
> >
> > Why?
>
> It might be potential benefit in some cases. Documentation says that
> standard Memory Write might supply more current data than in the CPU
> modified cache line and "trashing a line in the cache may trash some
> data that is more current that in the memory line". This allows to avoid
> potential retries and other performance degradation issues on the bus.
> Though, I dunno how to measure it.
>
> Would be enough to extend commit message by this paragraph?
That's better, yes.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-11-10 16:44 UTC | newest]
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2016-11-10 14:51 [PATCH v1 1/1] mfd: intel-lpss: Try to enable Memory-Write-Invalidate Andy Shevchenko
2016-11-10 14:59 ` Mika Westerberg
2016-11-10 15:22 ` Andy Shevchenko
2016-11-10 16:39 ` Mika Westerberg
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