On Thu, Oct 10, 2019 at 6:08 PM Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote:
>
> On Thu, Oct 10, 2019 at 3:50 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote:
> >
> > MediaTek XHCI host controller does not support 64-bit addressing despite
> > the AC64 bit of HCCPARAMS1 register being set. The platform-specific
> > glue sets the DMA mask to 32 bits on its own, but it has no effect,
> > because xhci_gen_setup() overrides it according to hardware
> > capabilities.
> >
> > Use the XHCI_NO_64BIT_SUPPORT quirk to tell the XHCI core to force
> > 32-bit DMA mask instead.
> >
> > Signed-off-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
>
> Can we add a Fixes: tag for stable backports?
> (after addressing the other comments of course)
>
The problem with Fixes: is that this patch depends on the quirk being
there, but the offending code was merged earlier. Do you know how to
handle such cases?
>
> > ---
> > drivers/usb/host/xhci-mtk.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> > index b18a6baef204a..4d101d52cc11b 100644
> > --- a/drivers/usb/host/xhci-mtk.c
> > +++ b/drivers/usb/host/xhci-mtk.c
> > @@ -395,6 +395,11 @@ static void xhci_mtk_quirks(struct device *dev, struct xhci_hcd *xhci)
> > xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
> > if (mtk->lpm_support)
> > xhci->quirks |= XHCI_LPM_SUPPORT;
> > + /*
> > + * MTK host controller does not support 64-bit addressing, despite
> > + * having the AC64 bit of the HCCPARAMS1 register set.
> > + */
> > + xhci->quirks |= XHCI_NO_64BIT_SUPPORT;
> > }
> >
> > /* called during probe() after chip reset completes */
> > @@ -488,11 +493,6 @@ static int xhci_mtk_probe(struct platform_device *pdev)
> > goto disable_clk;
> > }
> >
> > - /* Initialize dma_mask and coherent_dma_mask to 32-bits */
> > - ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> > - if (ret)
> > - goto disable_clk;
> > -
> > hcd = usb_create_hcd(driver, dev, dev_name(dev));
> > if (!hcd) {
> > ret = -ENOMEM;
> > --
> > 2.23.0.581.g78d2f28ef7-goog
> >
