From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3EC26EAD.8080200@embeddededge.com> Date: Wed, 14 May 2003 12:28:29 -0400 From: Dan Malek MIME-Version: 1.0 To: Gabriel Paubert Cc: Paul Mackerras , linuxppc-dev@lists.linuxppc.org Subject: Re: set_rtc_time() cleanup / normalization References: <20030512211733.B489EC6092@atlas.denx.de> <16065.31312.163813.582334@argo.ozlabs.ibm.com> <20030514154310.GC9430@iram.es> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Gabriel Paubert wrote: > Ask on the ntp lists first, I bet you'll upset a lot of people > if you suggest it. I'll bet no one is using it on a system that has an unpredictable latency, interrupt generating, i2c RTC, either. :-) The solution is to do like other architectures and allow (as Tom suggested) a selectable rtc update function. Although I may use a particular RTC driver, I may not want the update function that comes along with it. All we need is an indirect function pointer to the get/set functions that is initialized by the board set up functions. By default they should be null functions, if you want something else, put a pointer there. The fact is the current rtc update functions are not suitable for embedded boards that have to meet latency guarantees. They simply add overhead, often in a bad way, even if implemented correctly. Installing any kind of real-time enhancement (like RTLinux or RTAI) will cause a failure of the rtc update model because the update thread of control can be easily preempted. The solution is easy, you can find examples in other architectures, and we don't have to argue about it. Thanks. -- Dan ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/