From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, vkoul@kernel.org
Cc: yung-chuan.liao@linux.intel.com, sanyog.r.kale@intel.com,
linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org
Subject: Re: [PATCH 5/6] soundwire: qcom: update register read/write routine
Date: Tue, 2 Feb 2021 10:58:05 -0600 [thread overview]
Message-ID: <25ca91d5-4492-34f8-46df-4cb53c3a0b1b@linux.intel.com> (raw)
In-Reply-To: <4e3ebb99-5647-f71c-1256-a2c55bd9995f@linaro.org>
>>>>> generates interrupt after it successfully finishes. This is really
>>>>> overhead, limiting and not really necessary unless we are doing
>>>>> something special.
>>>>>
>>>>> We can simply read/write the fifo that should also give exactly
>>>>> what we need! This will also allow to read/write registers in
>>>>> interrupt context, which was not possible with the special
>>>>> command approach.
>>>>
>>>> This is really unclear, sorry.
>>>
>>> If read/writes are waiting for an interrupt, it becomes difficult to
>>> read or write to any registers from same interrupt handler!
>>
>> Well, yes, you need to handle the complete() at a lower level than the
>> code that initiates the transactions otherwise you self-deadlock.
>>
>> IIRC in the Intel initial code, the complete was in the handler and
>> the register IOs in the thread.
>>
> Yes, we did the same in previous version of the code, however with this
> patch reading/writing fifo directly without need of completion should
> remove that need of another thread!
Right, but you'll also write-off some command/control efficiency by
either sleeping too much before checking the status, or sleeping too
little and reading status from a transaction that's not finished.
next prev parent reply other threads:[~2021-02-02 17:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-29 17:32 [PATCH 0/6] soundwire: qcom: various improvements Srinivas Kandagatla
2021-01-29 17:32 ` [PATCH 1/6] soundwire: qcom: add support to missing transport params Srinivas Kandagatla
2021-01-29 19:20 ` Pierre-Louis Bossart
2021-02-01 15:50 ` Srinivas Kandagatla
2021-02-01 16:33 ` Pierre-Louis Bossart
2021-02-01 14:13 ` Vinod Koul
2021-02-01 15:50 ` Srinivas Kandagatla
2021-01-29 17:32 ` [PATCH 2/6] soundwire: qcom: extract version field Srinivas Kandagatla
2021-01-29 17:32 ` [PATCH 3/6] soundwire: qcom: set continue execution flag for ignored commands Srinivas Kandagatla
2021-01-29 19:21 ` Pierre-Louis Bossart
2021-02-01 14:16 ` Vinod Koul
2021-02-01 15:50 ` Srinivas Kandagatla
2021-02-02 4:46 ` Vinod Koul
2021-01-29 17:32 ` [PATCH 4/6] soundwire: qcom: start the clock during initialization Srinivas Kandagatla
2021-02-01 14:21 ` Vinod Koul
2021-02-01 15:50 ` Srinivas Kandagatla
2021-02-02 4:46 ` Vinod Koul
2021-01-29 17:32 ` [PATCH 5/6] soundwire: qcom: update register read/write routine Srinivas Kandagatla
2021-01-29 19:33 ` Pierre-Louis Bossart
2021-02-01 15:50 ` Srinivas Kandagatla
2021-02-01 16:42 ` Pierre-Louis Bossart
2021-02-02 10:19 ` Srinivas Kandagatla
2021-02-02 16:58 ` Pierre-Louis Bossart [this message]
2021-02-01 14:26 ` Vinod Koul
2021-02-01 15:50 ` Srinivas Kandagatla
2021-01-29 17:32 ` [PATCH 6/6] soundwire: qcom: add support to new interrupts Srinivas Kandagatla
2021-01-29 19:38 ` Pierre-Louis Bossart
2021-02-01 15:51 ` Srinivas Kandagatla
2021-02-01 14:31 ` Vinod Koul
2021-02-01 15:51 ` Srinivas Kandagatla
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