[Bug 215740] kernel warning: DMA-API: xhci_hcd: cacheline tracking EEXIST, overlapping mappings aren't supported

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=215740

Alan Stern (stern@rowland.harvard.edu) changed:

           What    |Removed                     |Added
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 Attachment #305444|0                           |1
        is obsolete|                            |
 Attachment #305456|0                           |1
        is obsolete|                            |

--- Comment #34 from Alan Stern (stern@rowland.harvard.edu) ---
Created attachment 305473
  --> https://bugzilla.kernel.org/attachment.cgi?id=305473&action=edit
Revised (again) diagnostics

I revised the test patch slightly.  Now the addresses are printed in hex, as
they should have been all along.  Also, there's a line to print out the
physical addresses pointed to by hub->buffer and hub->status when a new hub is
configured.  Here's the log for plugging in a hub, then plugging a mouse into
the hub:

[   32.757399] usb 1-1: new high-speed USB device number 5 using xhci_hcd
[   32.886200] usb 1-1: New USB device found, idVendor=05e3, idProduct=0608,
bcdDevice= 9.01
[   32.886444] usb 1-1: New USB device strings: Mfr=0, Product=1,
SerialNumber=0
[   32.886631] usb 1-1: Product: USB2.0 Hub
[   32.889566] hub 1-1:1.0: USB hub found
[   32.889813] usb 1-1: hub buffer at 100e71818, status at 100e71610
[   32.890499] hub 1-1:1.0: 4 ports detected
[   42.761267] usb 1-1.3: new low-speed USB device number 6 using xhci_hcd
[   42.833935] kauditd_printk_skb: 101 callbacks suppressed
[   42.844775] usb 1-1.3: New USB device found, idVendor=093a, idProduct=2510,
bcdDevice= 1.00
[   42.844841] usb 1-1.3: New USB device strings: Mfr=1, Product=2,
SerialNumber=0
[   42.844890] usb 1-1.3: Product: USB OPTICAL MOUSE
[   42.844933] usb 1-1.3: Manufacturer: PIXART
[   42.851150] input: PIXART USB OPTICAL MOUSE as
/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.3/1-1.3:1.0/0003:093A:2510.0009/input/input10
[   42.851585] hid-generic 0003:093A:2510.0009: input,hidraw8: USB HID v1.11
Mouse [PIXART USB OPTICAL MOUSE] on usb-0000:00:14.0-1.3/input0

The cache line size on this computer is 64 bytes, same as yours.  As you can
see, hub->buffer and hub->status were allocated in different cache lines, so
the DMA debugging routine did not detect an overlap.  That's why I didn't get
any error messages.

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