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mfd: intel-lpss: Try to enable Memory-Write-Invalidate 

Enable MWI mechanism if PCI bus master supports it.

It might be potential benefit in some cases. Documentation [1] 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.

[1] PCI System Architecture, 4th edition, ISBN: 0-201-30974-2, pp.117-119.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Andy Shevchenko 2016-11-15 12:37:04 +02:00 committed by Lee Jones
parent c5e589a171
commit 85a9419a25
1 changed files with 1 additions and 0 deletions
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1
drivers/mfd/intel-lpss-pci.c
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@ -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)