On Wed, 21 Jun 2006 17:43:36 +0100 Russell King <[EMAIL PROTECTED]> wrote:
| In the uart_update_mctrl() case, the purpose of the locking is to | prevent two concurrent changes to the modem control state resulting | in an inconsistency between the hardware and the software state. If | it's provable that it is always called from process context (and | it isn't called from a lock_kernel()-section or the lock_kernel() | section doesn't mind a rescheduling point being introduced there), | there's no problem converting that to a mutex. Ok, then I can submit my debug patch to answer these questions. might_sleep() can catch the lock_kernel()-section case right? | With get_mctrl(), the situation is slightly more complicated, because | we need to atomically update tty->hw_stopped in some circumstances | (that may also be modified from irq context.) Therefore, to give | the driver a consistent locking picture, the spinlock is _always_ | held. Is it too bad (wrong?) to only protect the tty->hw_stopped update by the spinlock? Then the call to get_mctrl() could be protected by a mutex, or is it messy? -- Luiz Fernando N. Capitulino All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
