mirror of
https://github.com/FEX-Emu/linux.git
synced 2025-01-02 07:11:12 +00:00
ff9c895f07
This patch (as1368) fixes a rather obscure bug in usbmon: When tracing URBs sent by the scatter-gather library, it accesses the data buffers while they are still mapped for DMA. The solution is to move the mapping and unmapping out of the s-g library and into the usual place in hcd.c. This requires the addition of new URB flag bits to describe the kind of mapping needed, since we have to call dma_map_sg() if the HCD supports native scatter-gather operation and dma_map_page() if it doesn't. The nice thing about having the new flags is that they simplify the testing for unmapping. The patch removes the only caller of usb_buffer_[un]map_sg(), so those functions are #if'ed out. A later patch will remove them entirely. As a result of this change, urb->sg will be set in situations where it wasn't set previously. Hence the xhci and whci drivers are adjusted to test urb->num_sgs instead, which retains its original meaning and is nonzero only when the HCD has to handle a scatterlist. Finally, even when a submission error occurs we don't want to hand URBs to usbmon before they are unmapped. The submission path is rearranged so that map_urb_for_dma() is called only for non-root-hub URBs and unmap_urb_for_dma() is called immediately after a submission error. This simplifies the error handling. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
||
|---|---|---|
| .. | ||
| atm | ||
| c67x00 | ||
| class | ||
| core | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.