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parisc: Remove 32-bit DMA enforcement from sba_iommu 

This breaks booting from sata_sil24 with the recent DMA change.
According to James Bottomley this was in to improve performance by
kicking the device into 32 bit descriptors, which are usually more
efficient, especially with older dual descriptor format cards like we
have on parisc systems.
Remove it for now to make DMA working again.

Fixes: dcc02c19cc ("sata_sil24: use dma_set_mask_and_coherent")
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Sven Schnelle 2019-09-24 17:01:31 +02:00 committed by Helge Deller
parent 513f7f747e
commit c32c47aa36
1 changed files with 0 additions and 8 deletions
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8
drivers/parisc/sba_iommu.c
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@ -678,14 +678,6 @@ static int sba_dma_supported( struct device *dev, u64 mask)
return(0);
}
/* Documentation/DMA-API-HOWTO.txt tells drivers to try 64-bit
* first, then fall back to 32-bit if that fails.
* We are just "encouraging" 32-bit DMA masks here since we can
* never allow IOMMU bypass unless we add special support for ZX1.
*/
if (mask > ~0U)
return 0;
ioc = GET_IOC(dev);
if (!ioc)
return 0;