On Wed, Dec 13, 2023 at 08:09:03AM +0000, Sakari Ailus wrote: > Hi Arnd, > > On Tue, Dec 12, 2023 at 10:18:04PM +0100, Arnd Bergmann wrote: > > From: Arnd Bergmann <arnd@xxxxxxxx> > > > > With clang-16, building without COMMON_CLK triggers a range check on > > udelay() because of a constant division-by-zero calculation: > > > > ld.lld: error: undefined symbol: __bad_udelay > > >>> referenced by mt9m114.c > > >>> drivers/media/i2c/mt9m114.o:(mt9m114_power_on) in archive vmlinux.a > > > > Avoid this by adding a Kconfig dependency that avoids the broken build. > > This sounds like an odd way to fix an issue with udelay(). On which arch > does it happen? Wouldn't it be better to fix the udelay() problem in the > source? > > A quick check reveals there are about 2400 files using udelay. After discussing with Tomi, I think the driver could be improved, too, by adding checks for clock frequency and avoiding an obvious potential division by zero if clk_get_rate() happens to return 0. Switching to fsleep() would probably address the Clang 16 issue, but that doesn't seem to be the primary cause here anyway. -- Sakari Ailus
