From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>,
Hans de Goede <hdegoede@redhat.com>,
Mark Gross <markgross@kernel.org>,
linux-kernel@vger.kernel.org, patches@lists.linux.dev,
platform-driver-x86@vger.kernel.org,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Prashant Malani <pmalani@chromium.org>
Subject: Re: [PATCH v2 2/3] platform/x86: intel_scu_ipc: Check status upon timeout in ipc_wait_for_interrupt()
Date: Wed, 6 Sep 2023 23:06:33 +0300 [thread overview]
Message-ID: <ZPjbyckhj63Gw+SB@smile.fi.intel.com> (raw)
In-Reply-To: <20230906180944.2197111-3-swboyd@chromium.org>
On Wed, Sep 06, 2023 at 11:09:42AM -0700, Stephen Boyd wrote:
> 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.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2023-09-06 20:06 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-06 18:09 [PATCH v2 0/3] platform/x86: intel_scu_ipc: Timeout fixes Stephen Boyd
2023-09-06 18:09 ` [PATCH v2 1/3] platform/x86: intel_scu_ipc: Check status after timeout in busy_loop() Stephen Boyd
2023-09-06 20:04 ` Andy Shevchenko
2023-09-06 20:14 ` Stephen Boyd
2023-09-06 20:20 ` Kuppuswamy Sathyanarayanan
2023-09-06 20:23 ` Stephen Boyd
2023-09-07 5:35 ` Mika Westerberg
2023-09-07 20:11 ` Stephen Boyd
2023-09-08 4:59 ` Mika Westerberg
2023-09-08 21:29 ` Stephen Boyd
2023-09-06 18:09 ` [PATCH v2 2/3] platform/x86: intel_scu_ipc: Check status upon timeout in ipc_wait_for_interrupt() Stephen Boyd
2023-09-06 20:06 ` Andy Shevchenko [this message]
2023-09-06 18:09 ` [PATCH v2 3/3] platform/x86: intel_scu_ipc: Fail IPC send if still busy Stephen Boyd
2023-09-06 20:13 ` Andy Shevchenko
2023-09-06 20:22 ` Stephen Boyd
2023-09-06 20:46 ` Andy Shevchenko
2023-09-06 20:59 ` Stephen Boyd
2023-09-07 5:29 ` Mika Westerberg
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