On Fri, Aug 07, 2015 at 08:18:48PM -0700, Duc Dang wrote:
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 890ad9d..5d03f8b 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -93,14 +93,14 @@ static int xhci_plat_probe(struct platform_device *pdev)
> if (irq < 0)
> return -ENODEV;
>
> - /* Initialize dma_mask and coherent_dma_mask to 32-bits */
> - ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
> - if (ret)
> - return ret;
> - if (!pdev->dev.dma_mask)
> - pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
> - else
> - dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
> + /* Try setting the coherent_dma_mask to 64 bits, then try 32 bits */
> + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> + if (ret) {
> + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> + if (ret)
> + return ret;
> + }
Note that dma_set_mask_and_coherent() and the original code are not
equivalent because of this:
if (!pdev->dev.dma_mask)
pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
If we know that pdev->dev.dma_mask will always be initialised at this
point, then the above change is fine. If not, it's introducing a
regression - dma_set_mask_and_coherent() will fail if pdev->dev.dma_mask
is NULL (depending on the architectures implementation of dma_set_mask()).
Prefixing the above change with the two lines I mention above would
ensure equivalent behaviour. Even if we do want to get rid of this,
I'd advise to do it as a separate patch after this change, which can
be independently reverted if there's problems with its removal.
--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.
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