6.5-stable review patch. If anyone has any objections, please let me know.
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From: Stephen Boyd swboyd@chromium.org
[ Upstream commit 427fada620733e6474d783ae6037a66eae42bf8c ]
It's possible for the completion in ipc_wait_for_interrupt() to timeout, simply because the interrupt was delayed in being processed. A timeout in itself is not an error. This driver should check the status register upon a timeout to ensure that scheduling or interrupt processing delays don't affect the outcome of the IPC return value.
CPU0 SCU ---- --- ipc_wait_for_interrupt() wait_for_completion_timeout(&scu->cmd_complete) [TIMEOUT] status[IPC_STATUS_BUSY]=0
Fix this problem by reading the status bit in all cases, regardless of the timeout. If the completion times out, we'll assume the problem was that the IPC_STATUS_BUSY bit was still set, but if the status bit is cleared in the meantime we know that we hit some scheduling delay and we should just check the error bit.
Cc: Prashant Malani pmalani@chromium.org Reviewed-by: 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: ed12f295bfd5 ("ipc: Added support for IPC interrupt mode") Signed-off-by: Stephen Boyd swboyd@chromium.org Link: https://lore.kernel.org/r/20230913212723.3055315-3-swboyd@chromium.org 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 --- drivers/platform/x86/intel_scu_ipc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c index 4c774ee8bb1bb..299c15312acb8 100644 --- a/drivers/platform/x86/intel_scu_ipc.c +++ b/drivers/platform/x86/intel_scu_ipc.c @@ -248,10 +248,12 @@ static inline int ipc_wait_for_interrupt(struct intel_scu_ipc_dev *scu) { int status;
- if (!wait_for_completion_timeout(&scu->cmd_complete, IPC_TIMEOUT)) - return -ETIMEDOUT; + wait_for_completion_timeout(&scu->cmd_complete, IPC_TIMEOUT);
status = ipc_read_status(scu); + if (status & IPC_STATUS_BUSY) + return -ETIMEDOUT; + if (status & IPC_STATUS_ERR) return -EIO;