On Wed, Jul 28, 2010 at 11:41:32AM +0200, Rapeli Mikko (EXT-Ixonos/Oulu) wrote: > From: Mikko Rapeli <ext-mikko.rapeli@xxxxxxxxx> > > Original patch: http://marc.info/?l=linux-omap&m=126522625032441&w=2 > > "Removes TWL4030 sleep script prior to rebooting, only on OMAP3. This is > necessary since DPLL3 reset causes SYS_OFFMODE pin to go low, resulting > in the sleep script being executed on TWL4030. This usually results in > VDD1 & VDD2 voltage collapse while ROM code is executing, followed by an > MPU Watch Dog reset or worse, an irrecoverable hang." > > Original patch resulted in a crash due to sleeping i2c calls late in the > reboot sequence. Here's how to trigger the crash: > > # cat /dev/urandom > /foo & > sync(); > reboot(LINUX_REBOOT_CMD_RESTART2); > > Kernel trace from 2.6.32: > > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > pgd = c0004000 > [00000000] *pgd=00000000 > Internal error: Oops: 805 [#2] PREEMPT > ... > [<c00b3210>] (exit_mmap+0x1d4/0x1f8) from [<c006069c>] (mmput+0x34/0x110) > [<c006069c>] (mmput+0x34/0x110) from [<c0064a90>] (exit_mm+0x140/0x180) > [<c0064a90>] (exit_mm+0x140/0x180) from [<c00668ec>] (do_exit+0x5d8/0x6ac) > [<c00668ec>] (do_exit+0x5d8/0x6ac) from [<c0035858>] (die+0x2d4/0x2e0) > [<c0035858>] (die+0x2d4/0x2e0) from [<c0035904>] (baddataabort+0x0/0x50) > [<c0035904>] (baddataabort+0x0/0x50) from [<c0274ff4>] (i2c_transfer+0xec/0x104) > [<c0274ff4>] (i2c_transfer+0xec/0x104) from [<00000001>] (0x1) > > Fix is to move reboot preparations into a reboot notifier. > And what if we get an OMAP3 watchdog reset ? In this case there is no software to remove the script... Cheers, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
