On Tue, 2 Aug 2016, Marc Ohlf wrote: > On Mon, Aug 01, 2016 at 06:07:17PM +0200, Alan Stern wrote: > > On Mon, 1 Aug 2016, Marc Ohlf wrote: > > > > > In ehci_turn_off_all_ports() all EHCI port register bits > > > (except the PORT_RWC_BITS) are set to zero. > > > > Even the PORT_WRC_BITS are set to 0. Oddly enough, the way to set > > those bits to 0 is to write a 1 to them (see Table 2-16 in the EHCI > > spec). > > Thanks for correction, i will improve that in an v2. > > > > > > On some hardware, this can lead to an system hang, > > > when ehci_port_power() accesses the already cleaned registers. > > > > > > This patch changes the order of cleanup. > > > First call ehci_port_power() which respects the current bits in > > > port status registers > > > and afterwards cleanup the hard way by setting everything else to zero. > > > > > > Signed-off-by: Marc Ohlf <[email protected]> > > > --- > > > drivers/usb/host/ehci-hcd.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c > > > index a962b89..1e5f529 100644 > > > --- a/drivers/usb/host/ehci-hcd.c > > > +++ b/drivers/usb/host/ehci-hcd.c > > > @@ -332,11 +332,11 @@ static void ehci_turn_off_all_ports(struct ehci_hcd > > > *ehci) > > > int port = HCS_N_PORTS(ehci->hcs_params); > > > > > > while (port--) { > > > - ehci_writel(ehci, PORT_RWC_BITS, > > > - &ehci->regs->port_status[port]); > > > spin_unlock_irq(&ehci->lock); > > > ehci_port_power(ehci, port, false); > > > spin_lock_irq(&ehci->lock); > > > + ehci_writel(ehci, PORT_RWC_BITS, > > > + &ehci->regs->port_status[port]); > > > } > > > } > > > > I'm new to the mailing lists, so I've some questions. > > > Acked-by: Alan Stern <[email protected]> > > I should include your Ack in my v2 patch signoff area, right?
Yes. > > > > This should be marked for the -stable kernels as well. > > Marking this for -stable kernels means cc it to stable mailing list, right? No, it means adding: CC: <[email protected]> in among the Signed-off-by: and Acked-by: lines. This tag will automatically cause the patch to be added to the -stable queue when it gets accepted. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
