-
由 Len Brown 提交于
The following commit: a9bcaa02 ("x86/smpboot: Remove SIPI delays from cpu_up()") Caused some Intel Core2 processors to time-out when bringing up CPU #1, resulting in the missing of that CPU after bootup. That patch reduced the SIPI delays from udelay() 300, 200 to udelay() 0, 0 on modern processors. Several Intel(R) Core(TM)2 systems failed to bring up CPU #1 10/10 times after that change. Increasing either of the SIPI delays to udelay(1) results in success. So here we increase both to udelay(10). While this may be 20x slower than the absolute minimum, it is still 20x to 30x faster than the original code. Tested-by: NDonald Parsons <dparsons@brightdsl.net> Tested-by: NShane <shrybman@teksavvy.com> Signed-off-by: NLen Brown <len.brown@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dparsons@brightdsl.net Cc: shrybman@teksavvy.com Link: http://lkml.kernel.org/r/6dd554ee8945984d85aafb2ad35793174d068af0.1444968087.git.len.brown@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
fcafddec