On Tue, 22 Jul 2003, Wolfgang Denk wrote: > > I share your dislike of updating the RTC for performance reasons; these > > There are more problems with the 11 minute mode. We ran into this > issue for hard on some PowerPC systems. Assume a situation where the > RTC is connected through a I2C bus. Problem 1: normally the i2c > drivers will be loaded prety late, which means the system will run > initially with an undefined time. Problem 2: on some actions a i2c > transfer involves programming an on-chip i2c controller, which will > perform the task and then signal it's done by an interrupt. On such a > system the 11 minute mode will crash the system because rtc_set will > be called from interrupt contect itself. > > There was a somewhat controverse discussion on the linuxppc_dev > mailing list, without a real solution. A possible solution is to make the update configurable with a sysctl. It really begs for it. I think it may be worth discussing at the LKML. Additionally Ulrich Windl may wish to share a few thoughts on the matter. -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available +
