From 7b81cb6bddd2c4f2489506771070924bd0ae9902 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 16 Aug 2019 08:24:32 +0200 Subject: usb: add a HCD_DMA flag instead of guestimating DMA capabilities The usb core is the only major place in the kernel that checks for a non-NULL device dma_mask to see if a device is DMA capable. This is generally a bad idea, as all major busses always set up a DMA mask, even if the device is not DMA capable - in fact bus layers like PCI can't even know if a device is DMA capable at enumeration time. This leads to lots of workaround in HCD drivers, and also prevented us from setting up a DMA mask for platform devices by default last time we tried. Replace this guess with an explicit HCD_DMA that is set by drivers that appear to have DMA support. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20190816062435.881-4-hch@lst.de Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/uhci-pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/usb/host/uhci-pci.c') diff --git a/drivers/usb/host/uhci-pci.c b/drivers/usb/host/uhci-pci.c index 0dd944277c99..0fa3d72bae26 100644 --- a/drivers/usb/host/uhci-pci.c +++ b/drivers/usb/host/uhci-pci.c @@ -261,7 +261,7 @@ static const struct hc_driver uhci_driver = { /* Generic hardware linkage */ .irq = uhci_irq, - .flags = HCD_USB11, + .flags = HCD_DMA | HCD_USB11, /* Basic lifecycle operations */ .reset = uhci_pci_init, -- cgit v1.2.3