• Stefano Babic's avatar
    usb: musb: am35xx: drop spurious unplugging a device · 6ff1f3d3
    Stefano Babic authored
    On AM3517, tx and rx interrupt are detected together with
    the disconnect event. This generates a kernel panic in musb_interrupt,
    because rx / tx are handled after disconnect.
    This issue was seen on a Technexion's TAM3517 SOM. Unplugging a device,
    tx / rx interrupts together with disconnect are detected. This brings
    to kernel panic like this:
    
    [   68.526153] Unable to handle kernel NULL pointer dereference at virtual address 00000011
    [   68.534698] pgd = c0004000
    [   68.537536] [00000011] *pgd=00000000
    [   68.541351] Internal error: Oops: 17 [#1] ARM
    [   68.545928] Modules linked in:
    [   68.549163] CPU: 0    Not tainted  (3.6.0-rc5-00020-g9e05905 #178)
    [   68.555694] PC is at rxstate+0x8/0xdc
    [   68.559539] LR is at musb_interrupt+0x98/0x858
    [   68.564239] pc : [<c035cd88>]    lr : [<c035af1c>]    psr: 40000193
    [   68.564239] sp : ce83fb40  ip : d0906410  fp : 00000000
    [   68.576293] r10: 00000000  r9 : cf3b0e40  r8 : 00000002
    [   68.581817] r7 : 00000019  r6 : 00000001  r5 : 00000001  r4 : 000000d4
    [   68.588684] r3 : 00000000  r2 : 00000000  r1 : ffffffcc  r0 : cf23c108
    [   68.595550] Flags: nZcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment ke
    
    Note: this behavior is not seen with a USB hub, while it is
    easy to reproduce connecting a USB-pen directly to the USB-A of
    the board.
    
    Drop tx / rx interrupts if disconnect is detected.
    Signed-off-by: default avatarStefano Babic <sbabic@denx.de>
    CC: Felipe Balbi <balbi@ti.com>
    Cc: stable@vger.kernel.org # 3.5 3.6
    Tested-by: default avatarDmitry Lifshitz <lifshitz@compulab.co.il>
    Tested-by: default avatarIgor Grinberg <grinberg@compulab.co.il>
    Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
    6ff1f3d3
am35x.c 16.6 KB