On Sat, 20 Nov 2021 at 00:09, Tom Rini trini@konsulko.com wrote:
On Fri, Nov 19, 2021 at 10:52:27PM +0100, Heinrich Schuchardt wrote:
Am 19. November 2021 22:33:04 MEZ schrieb Tom Rini trini@konsulko.com:
If we look at the path that bootm/booti take when preparing to boot the OS, we see that as part of (or prior to calling do_bootm_states, explicitly) the process, bootm_disable_interrupts() is called prior to announce_and_cleanup() which is where udc_disconnect() / board_quiesce_devices() / dm_remove_devices_flags() are called from. In the EFI path, these are called afterwards. In efi_exit_boot_services() however we have been calling bootm_disable_interrupts() after the above functions, as part of ensuring that we disable interrupts as required by the spec. However, bootm_disable_interrupts() is also where we go and call usb_stop(). While this has been fine before, on the TI J721E platform this leads us to an exception. This exception seems likely to be the case that we're trying to stop devices that we have already disabled clocks for. The most direct way to handle this particular
This patch may hide an error on your board but obviously does not address the real problem.
I don't think it 'hides' it. I think it's the other way around, this board exposes the problem. In any case I think disabling irq's etc make sense to run before we disable devices completely.
If dependencies in the shut down sequence should exist, we need to consider them in the driver model.
Yes agree 100% here.
What is your plan to analyze the problem?
I'm not sure there is a different problem to solve here. It's unsafe to call the "shut everything down" function, which is what usb_stop() is, after having shut everything down. We may be able to stop calling usb_stop() as any sort of shutdown should already have happened via driver model, which is what we see now.
Linux has CONFIG_EFI_DISABLE_PCI_DMA to deal with similar problems on PCI devices. Basically it disables busmastering until linux properly configures the SMMU. I think disabling the devices before handing over to the OS (when possible) is a good policy. In any case I think this patch is reasonable since it at lest makes EFI and bootm/i behave similarly. I'll go have a look on bootm/i and cleanup the whole thing at some point.
Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org
-- Tom