From mboxrd@z Thu Jan 1 00:00:00 1970 In-Reply-To: <13981.45420.95483.559227@lassi.cygnus.co.uk> Date: Thu, 14 Jan 1999 14:27:52 +0100 To: linuxppc-dev@lists.linuxppc.org CC: Cort Dougan , Jesper Skov From: Benjamin Herrenschmidt Subject: Re: Synchronization [was Re: The Magic Show: kernel_map() disappearing] Message-Id: <19990114142752.015604@mail.mipsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Thu, Jan 14, 1999, Jesper Skov wrote: >We would want to use eieio for drivers and such accessing their >controller in a strict serialized manner. We would want to use sync >for SMP related stuff since it ensures, well, synchronization between >multiple CPUs wrt memory access. And I'll add the usual warning: If the device is a PCI device and you need to make sure that the write actually reached the device (for example making sure the interrupt enable bits are set before re-enabling the interrupts on the CPU), you should add a read from the same device (from the same bus should be enough) to make sure tall the bridges in the path to the device completed their write. Remember that a write to PCI is usually a "posted write" and so is asynchronous, regardless of eieio or sync's done on the CPU. -- E-Mail: BenH. Web : [[ This message was sent via the linuxppc-dev mailing list. Replies are ]] [[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]] [[ reply is of general interest. To unsubscribe from linuxppc-dev, send ]] [[ the message 'unsubscribe' to linuxppc-dev-request@lists.linuxppc.org ]]