On Sat, Nov 13, 2021, at 15:29, Fabio Aiuto wrote:
> in case of a PCI dwc3 controller, leave the default DMA
> mask. Calling of a 64 bit DMA mask breaks the driver on
> cherrytrail based tablets like Cyberbook T116.
>
> Fixes: 45d39448b4d0 ("usb: dwc3: support 64 bit DMA in platform driver")
> Reported-by: Hans De Goede <hdegoede@xxxxxxxxxx>
> Tested-by: Fabio Aiuto <fabioaiuto83@xxxxxxxxx>
> Signed-off-by: Fabio Aiuto <fabioaiuto83@xxxxxxxxx>
> ---
> drivers/usb/dwc3/core.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 643239d7d370..f4c09951b517 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1594,9 +1594,11 @@ static int dwc3_probe(struct platform_device *pdev)
>
> dwc3_get_properties(dwc);
>
> - ret = dma_set_mask_and_coherent(dwc->sysdev, DMA_BIT_MASK(64));
> - if (ret)
> - return ret;
> + if (!dwc->sysdev_is_parent) {
Are you sure it's the dwc3 controller that limits DMA to 32 bit addresses and
not the PCI bus itself?
I also think the xhci driver will call dma_set_mask_and_coherent again
later on when dwc3 is used in host mode.
Sven
