1. 16 11月, 2010 1 次提交
    • S
      xhci: Fix command ring replay after resume. · 89821320
      Sarah Sharp 提交于
      Andiry's xHCI bus suspend patch introduced the possibly of a host
      controller replaying old commands on the command ring, if the host
      successfully restores the registers after a resume.
      
      After a resume from suspend, the xHCI driver must restore the registers,
      including the command ring pointer.  I had suggested that Andiry set the
      command ring pointer to the current command ring dequeue pointer, so that
      the driver wouldn't have to zero the command ring.
      
      Unfortunately, setting the command ring pointer to the current dequeue
      pointer won't work because the register assumes the pointer is 64-byte
      aligned, and TRBs on the command ring are 16-byte aligned.  The lower
      seven bits will always be masked off, leading to the written pointer being
      up to 3 TRBs behind the intended pointer.
      
      Here's a log excerpt.  On init, the xHCI driver places a vendor-specific
      command on the command ring:
      
      [  215.750958] xhci_hcd 0000:01:00.0: Vendor specific event TRB type = 48
      [  215.750960] xhci_hcd 0000:01:00.0: NEC firmware version 30.25
      [  215.750962] xhci_hcd 0000:01:00.0: Command ring deq = 0x3781e010 (DMA)
      
      When we resume, the command ring dequeue pointer to be written should have
      been 0x3781e010.  Instead, it's 0x3781e000:
      
      [  235.557846] xhci_hcd 0000:01:00.0: // Setting command ring address to 0x3781e001
      [  235.557848] xhci_hcd 0000:01:00.0: `MEM_WRITE_DWORD(3'b000, 64'hffffc900100bc038, 64'h3781e001, 4'hf);
      [  235.557850] xhci_hcd 0000:01:00.0: `MEM_WRITE_DWORD(3'b000, 32'hffffc900100bc020, 32'h204, 4'hf);
      [  235.557866] usb usb9: root hub lost power or was reset
      
      (I can't see the results of this bug because the xHCI restore always fails
      on this box, and the xHCI driver re-allocates everything.)
      
      The fix is to zero the command ring and put the software and hardware
      enqueue and dequeue pointer back to the beginning of the ring.  We do this
      before the system suspends, to be paranoid and prevent the BIOS from
      starting the host without clearing the command ring pointer, which might
      cause the host to muck with stale memory.  (The pointer isn't required to
      be in the suspend power well, but it could be.)  The command ring pointer
      is set again after the host resumes.
      Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
      Tested-by: NAndiry Xu <andiry.xu@amd.com>
      89821320
  2. 14 11月, 2010 3 次提交
  3. 13 11月, 2010 16 次提交
  4. 12 11月, 2010 20 次提交