On 09/11/2014 05:22 PM, Gerd Hoffmann wrote: > On Do, 2014-09-11 at 17:11 +1000, Alexey Kardashevskiy wrote: >> When the guest performs kexec() (for example, as a part of kdump), >> new kernel does PCI probing. As a part of it, PCI_COMMAND_MASTER >> gets disabled which disables bus master memory region. >> Since ohci_frame_boundary() timer is not stopped at this point >> as OHCI device was not reset, the device tries accessing DMA memory, >> fails and ends up in ohci_die() producing errors: >> >> usb-ohci: HCCA read error at 30000000 >> ohci_die: DMA error > > Which is the correct behavior. > > IMHO the kernel should stop ohci before doing kexec.
To be precise, it is kdump. > Independant of that we can move the ohci error logging to tracepoints, > so ohci emulation is silent by default. That is the other way to go, yes. -- Alexey
