linux-kernel - Re: [PATCH v1 1/2] scsi: ufs: core: Remove UFS_DEVICE_QUIRK_DELAY_AFTER

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Message-ID: <450e834545af935010ffc4f9079e56e47851f197.camel@mediatek.com>
Date: Thu, 2 Oct 2025 07:57:08 +0000
From: Peter Wang (王信友) <peter.wang@...iatek.com>
To: "avri.altman@....com" <avri.altman@....com>, "quic_cang@...cinc.com"
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Subject: Re: [PATCH v1 1/2] scsi: ufs: core: Remove
 UFS_DEVICE_QUIRK_DELAY_AFTER_LPM quirk

On Wed, 2025-10-01 at 13:57 -0700, Bao D. Nguyen wrote:
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 2e1fa8c..45e509b 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -9738,10 +9738,9 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba
> *hba)
>         }
> 
>         /*
> -        * Some UFS devices require delay after VCC power rail is
> turned-off.
> +        * All UFS devices require delay after VCC power rail is
> turned-off.
>          */
> -       if (vcc_off && hba->vreg_info.vcc &&
> -               hba->dev_quirks & UFS_DEVICE_QUIRK_DELAY_AFTER_LPM)
> +       if (vcc_off && hba->vreg_info.vcc)
>                 usleep_range(5000, 5100);
>  }
> 
> diff --git a/drivers/ufs/host/ufs-mediatek.c b/drivers/ufs/host/ufs-
> mediatek.c
> index f902ce0..5c204d1 100644
> --- a/drivers/ufs/host/ufs-mediatek.c
> +++ b/drivers/ufs/host/ufs-mediatek.c
> @@ -40,8 +40,7 @@ static int  ufs_mtk_config_mcq(struct ufs_hba *hba,
> bool irq);
>  static const struct ufs_dev_quirk ufs_mtk_dev_fixups[] = {
>         { .wmanufacturerid = UFS_ANY_VENDOR,
>           .model = UFS_ANY_MODEL,
> -         .quirk = UFS_DEVICE_QUIRK_DELAY_AFTER_LPM |
> -               UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM },
> +         .quirk = UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM },
>         { .wmanufacturerid = UFS_VENDOR_SKHYNIX,
>           .model = "H9HQ21AFAMZDAR",
>           .quirk = UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES },
> @@ -1713,15 +1712,13 @@ static void ufs_mtk_fixup_dev_quirks(struct
> ufs_hba *hba)
>  {
>         ufshcd_fixup_dev_quirks(hba, ufs_mtk_dev_fixups);
> 
> -       if (ufs_mtk_is_broken_vcc(hba) && hba->vreg_info.vcc &&
> -           (hba->dev_quirks & UFS_DEVICE_QUIRK_DELAY_AFTER_LPM)) {
> +       if (ufs_mtk_is_broken_vcc(hba) && hba->vreg_info.vcc) {
> 

Hi Bao,

Adding a delay is not reasonable if we have decided to
keep VCC always on.

Thanks
Peter


>                 hba->vreg_info.vcc->always_on = true;
>                 /*
>                  * VCC will be kept always-on thus we don't
> -                * need any delay during regulator operations
> +                * need any delay before putting device's VCC in LPM
> mode.
>                  */
> -               hba->dev_quirks &=
> ~(UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM |
> -                       UFS_DEVICE_QUIRK_DELAY_AFTER_LPM);
> +               hba->dev_quirks &=
> ~UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM;
>