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From: Asutosh Das <quic_asutoshd@quicinc.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: <quic_cang@quicinc.com>, <martin.petersen@oracle.com>,
	<linux-scsi@vger.kernel.org>, <quic_nguyenb@quicinc.com>,
	<quic_xiaosenh@quicinc.com>, <stanley.chu@mediatek.com>,
	<eddie.huang@mediatek.com>, <daejun7.park@samsung.com>,
	<avri.altman@wdc.com>, <mani@kernel.org>, <beanhuo@micron.com>,
	<quic_richardp@quicinc.com>, <linux-arm-msm@vger.kernel.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 03/17] ufs: core: Introduce Multi-circular queue capability
Date: Fri, 28 Oct 2022 09:51:16 -0700	[thread overview]
Message-ID: <20221028165116.GC9077@asutoshd-linux1.qualcomm.com> (raw)
In-Reply-To: <14a5925b-df2b-3f84-ed99-b4157c0a1b21@acm.org>

On Thu, Oct 27 2022 at 14:10 -0700, Bart Van Assche wrote:
>On 10/20/22 11:03, Asutosh Das wrote:
>>+
>>+	/*
>>+	 * This capability allows the host controller driver to turn on/off
>>+	 * MCQ mode. MCQ mode may be used to increase performance.
>>+	 */
>>+	UFSHCD_CAP_MCQ_EN				= 1 << 12,
>>  };
>
>I prefer that the above flag would only be introduced after a need 
>appears to disable MCQ, e.g. discovery of a host controller that is 
>too broken to enable MCQ.
>
I think this flag is useful during chip bring-ups &/or debugs.
Considering that this is a fairly new hardware block even though the HC supports
MCQ there could be times to keep it disabled.

>Since UFSHCI 4.0 controllers must support UFSHCI 3.0, shouldn't users 
>have a way to disable MCQ, e.g. via a kernel module parameter?
>
I can add a kernel module parameter to disable MCQ.
I think adding it to host driver (e.g. ufs-qcom) would be good.
Please let me know if you have a better place in mind.

>Thanks,
>
>Bart.

  reply	other threads:[~2022-10-28 16:51 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1666288432.git.quic_asutoshd@quicinc.com>
2022-10-20 18:03 ` [PATCH v3 01/17] ufs: core: Probe for ext_iid support Asutosh Das
2022-10-27 21:02   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 02/17] ufs: core: Optimize duplicate code to read extended feature Asutosh Das
2022-10-27 21:05   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 03/17] ufs: core: Introduce Multi-circular queue capability Asutosh Das
2022-10-27 21:09   ` Bart Van Assche
2022-10-28 16:51     ` Asutosh Das [this message]
2022-10-28 21:44       ` Bart Van Assche
2022-10-30 12:11     ` Avri Altman
2022-10-20 18:03 ` [PATCH v3 04/17] ufs: core: Defer adding host to scsi if mcq is supported Asutosh Das
2022-10-27 21:18   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 05/17] ufs: core: mcq: Introduce Multi Circular Queue Asutosh Das
2022-10-27 21:33   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 06/17] ufs: core: mcq: Configure resource regions Asutosh Das
2022-10-26  9:14   ` Eddie Huang
2022-10-20 18:03 ` [PATCH v3 07/17] ufs: core: mcq: Calculate queue depth Asutosh Das
2022-10-27 21:52   ` Bart Van Assche
2022-10-30 11:43     ` Avri Altman
2022-10-31 19:34       ` Asutosh Das
2022-10-31 19:24     ` Asutosh Das
2022-10-31 19:42       ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 08/17] ufs: core: mcq: Allocate memory for mcq mode Asutosh Das
2022-10-27 21:38   ` Bart Van Assche
2022-10-30 12:28   ` Avri Altman
2022-10-31 19:39     ` Asutosh Das
2022-10-20 18:03 ` [PATCH v3 09/17] ufs: core: mcq: Configure operation and runtime interface Asutosh Das
2022-10-27 22:01   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 10/17] ufs: core: mcq: Use shared tags for MCQ mode Asutosh Das
2022-10-28 21:47   ` Bart Van Assche
2022-10-30 13:06   ` Avri Altman
2022-11-01 16:29     ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 11/17] ufs: core: Prepare ufshcd_send_command for mcq Asutosh Das
2022-10-28 21:49   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 12/17] ufs: core: mcq: Find hardware queue to queue request Asutosh Das
2022-10-28 21:53   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 13/17] ufs: core: Prepare for completion in mcq Asutosh Das
2022-10-28 21:56   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 14/17] ufs: mcq: Add completion support of a cqe Asutosh Das
2022-10-28 22:05   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 15/17] ufs: core: mcq: Add completion support in poll Asutosh Das
2022-10-28 22:07   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 16/17] ufs: core: mcq: Enable Multi Circular Queue Asutosh Das
2022-10-28 22:07   ` Bart Van Assche
2022-10-20 18:03 ` [PATCH v3 17/17] ufs: qcom-host: Enable multi circular queue capability Asutosh Das
2022-10-28 22:08   ` Bart Van Assche
2022-11-01 18:47     ` Asutosh Das

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