linux-kernel - Re: [PATCH] ufs: core: add caps UFSHCD_CAP_MCQ

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ada5e578b647b71e85ab1a7eccd7401f7b4d2700.camel@mediatek.com>
Date: Tue, 22 Apr 2025 07:51:39 +0000
From: Peter Wang (王信友) <peter.wang@...iatek.com>
To: "tanghuan@...o.com" <tanghuan@...o.com>
CC: "avri.altman@....com" <avri.altman@....com>, "ebiggers@...gle.com"
	<ebiggers@...gle.com>, "quic_nguyenb@...cinc.com" <quic_nguyenb@...cinc.com>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	"manivannan.sadhasivam@...aro.org" <manivannan.sadhasivam@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"alim.akhtar@...sung.com" <alim.akhtar@...sung.com>, "bvanassche@....org"
	<bvanassche@....org>, "minwoo.im@...sung.com" <minwoo.im@...sung.com>,
	"opensource.kernel@...o.com" <opensource.kernel@...o.com>,
	"James.Bottomley@...senPartnership.com"
	<James.Bottomley@...senPartnership.com>, "martin.petersen@...cle.com"
	<martin.petersen@...cle.com>
Subject: Re: [PATCH] ufs: core: add caps UFSHCD_CAP_MCQ_EN

On Tue, 2025-04-22 at 14:25 +0800, Huan Tang wrote:
> 
> Hi Peter sir,
> 
> 
> 
> Thanks for you reply!
> 
> I found that using low-end UFS in SoCs that support MCQ may cause
> 
> device latency to reach extreme values.
> 
> 
> 
> My idea is that after having this patch, I can add hba->caps &=
> 
> ~UFSHCD_CAP_MCQ_EN to disable mcq via ufs-qcom.c or ufs-mediatek.c.
> 
> 
> 
> Do you mean to add a caps UFSHCD_CAP_MCQ_DISABLE?
> 
> Or remove hba->caps |= UFSHCD_CAP_MCQ_EN in ufshcd_alloc_host,
> 
> and then add hba->caps |= UFSHCD_CAP_MCQ_EN in ufs-xxx.c, such as
> ufs-mediatek.c?
> 
> 
> 
> Thanks
> 
> Huan

Hi Huan,

What I mean is that you need upstream code to disable this flag. 
hba->caps &= ~UFSHCD_CAP_MCQ_EN

But this seems a bit strange to me, as MCQ is a UFS host feature. 
It shouldn't be related to the old ufs2.x device. 
If it is ultimately confirmed to be an issue with the UFS device, 
you can add a device quirk to disable this flag.

Thanks.
Peter