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linux/drivers/platform
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Stephen Boyd 21efa88e77 platform/x86: intel_scu_ipc: Fail IPC send if still busy 
[ Upstream commit 85e654c9f7 ]

It's possible for interrupts to get significantly delayed to the point
that callers of intel_scu_ipc_dev_command() and friends can call the
function once, hit a timeout, and call it again while the interrupt
still hasn't been processed. This driver will get seriously confused if
the interrupt is finally processed after the second IPC has been sent
with ipc_command(). It won't know which IPC has been completed. This
could be quite disastrous if calling code assumes something has happened
upon return from intel_scu_ipc_dev_simple_command() when it actually
hasn't.

Let's avoid this scenario by simply returning -EBUSY in this case.
Hopefully higher layers will know to back off or fail gracefully when
this happens. It's all highly unlikely anyway, but it's better to be
correct here as we have no way to know which IPC the status register is
telling us about if we send a second IPC while the previous IPC is still
processing.

Cc: Prashant Malani <pmalani@chromium.org>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Fixes: ed12f295bf ("ipc: Added support for IPC interrupt mode")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20230913212723.3055315-5-swboyd@chromium.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-10-06 13:18:06 +02:00
..
chrome platform/chrome: cros_ec_chardev: fix kernel data leak from ioctl 2023-03-30 12:47:50 +02:00
goldfish platform/goldfish: Convert pipe tasklet to threaded irq 2021-01-27 14:57:06 +01:00
mellanox platform/mellanox: mlxbf-pmc: Fix reading of unprogrammed events 2023-09-19 12:23:04 +02:00
mips MIPS: Loongson-3: fix compile mips cpu_hwmon as module build error. 2022-06-22 14:21:58 +02:00
olpc platform/olpc: Fix uninitialized data in debugfs write 2022-08-17 14:23:58 +02:00
surface platform/surface: aggregator: Allow completion work-items to be executed in parallel 2023-06-14 11:13:00 +02:00
x86 platform/x86: intel_scu_ipc: Fail IPC send if still busy 2023-10-06 13:18:06 +02:00
Kconfig platform: Add Surface platform directory 2020-10-27 12:51:03 +01:00
Makefile platform: Add Surface platform directory 2020-10-27 12:51:03 +01:00