From: Vinod Koul <vkoul@kernel.org>
To: Richard Fitzgerald <rf@opensource.cirrus.com>
Cc: yung-chuan.liao@linux.intel.com,
pierre-louis.bossart@linux.intel.com, sanyog.r.kale@intel.com,
alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
patches@opensource.cirrus.com
Subject: Re: [PATCH v4 0/5] soundwire: Fixes for spurious and missing UNATTACH
Date: Tue, 20 Sep 2022 10:29:43 +0530 [thread overview]
Message-ID: <YylIv9VGYl3VqVIZ@matsya> (raw)
In-Reply-To: <20220914160248.1047627-1-rf@opensource.cirrus.com>
On 14-09-22, 17:02, Richard Fitzgerald wrote:
> The bus and cadence code has several bugs that cause UNATTACH notifications
> to either be sent spuriously or to be missed.
>
> These can be seen occasionally with a single peripheral on the bus, but are
> much more frequent with multiple peripherals, where several peripherals
> could change state and report in consecutive PINGs.
>
> The root of all of these bugs seems to be a code design flaw that assumed
> every PING status change would be handled separately. However, PINGs are
> handled by a workqueue function and there is no guarantee when that function
> will be scheduled to run or how much CPU time it will receive. PINGs will
> continue while the work function is handling a snapshot of a previous PING
> so the code must take account that (a) status could change during the
> work function and (b) there can be a backlog of changes before the IRQ work
> function runs again.
Applied, thanks
--
~Vinod
prev parent reply other threads:[~2022-09-20 5:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-14 16:02 [PATCH v4 0/5] soundwire: Fixes for spurious and missing UNATTACH Richard Fitzgerald
2022-09-14 16:02 ` [PATCH v4 1/5] soundwire: cadence: fix updating slave status when a bus has multiple peripherals Richard Fitzgerald
2022-09-14 16:02 ` [PATCH v4 2/5] soundwire: bus: Don't lose unattach notifications Richard Fitzgerald
2022-09-14 16:02 ` [PATCH v4 3/5] soundwire: bus: Don't re-enumerate before status is UNATTACHED Richard Fitzgerald
2022-09-14 16:02 ` [PATCH v4 4/5] soundwire: cadence: Fix lost ATTACHED interrupts when enumerating Richard Fitzgerald
2022-09-14 16:02 ` [PATCH v4 5/5] soundwire: bus: Don't exit early if no device IDs were programmed Richard Fitzgerald
2022-09-20 4:59 ` Vinod Koul [this message]
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