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| author | Christoph Hellwig <hch@lst.de> | 2019-08-16 08:24:32 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-21 10:03:35 -0700 |
| commit | 7b81cb6bddd2c4f2489506771070924bd0ae9902 (patch) | |
| tree | e93409bd98a306bc26cc19c1c6a29f70029d42a0 /drivers/usb/core/hcd.c | |
| parent | 0709831a50d31b3caf2237e8d7fe89e15b0d919d (diff) | |
| download | linux-stable-7b81cb6bddd2c4f2489506771070924bd0ae9902.tar.gz linux-stable-7b81cb6bddd2c4f2489506771070924bd0ae9902.tar.bz2 linux-stable-7b81cb6bddd2c4f2489506771070924bd0ae9902.zip | |
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 <hch@lst.de>
Link: https://lore.kernel.org/r/20190816062435.881-4-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/hcd.c')
| -rw-r--r-- | drivers/usb/core/hcd.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 8592c0344fe8..add2af4af766 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -2454,7 +2454,6 @@ struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver, hcd->self.controller = dev; hcd->self.sysdev = sysdev; hcd->self.bus_name = bus_name; - hcd->self.uses_dma = (sysdev->dma_mask != NULL); timer_setup(&hcd->rh_timer, rh_timer_func, 0); #ifdef CONFIG_PM |