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 --- include/linux/usb.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/usb.h') diff --git a/include/linux/usb.h b/include/linux/usb.h index b548c530f988..e656e7b4b1e4 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -426,7 +426,6 @@ struct usb_bus { struct device *sysdev; /* as seen from firmware or bus */ int busnum; /* Bus number (in order of reg) */ const char *bus_name; /* stable id (PCI slot_name etc) */ - u8 uses_dma; /* Does the host controller use DMA? */ u8 uses_pio_for_control; /* * Does the host controller use PIO * for control transfers? -- cgit v1.2.3