Re: [PATCH 2/3] scsi: ufs: core: Tolerate RX_FOM read failures in TX EQTR

[Manivannan Sadhasivam]

On Sat, Jun 20, 2026 at 01:03:21AM -0700, Can Guo wrote:
> ufshcd_get_rx_fom() aborted TX EQTR when a per-lane RX_FOM DME read failed.
> That makes the whole training flow fragile even though these reads can be
> treated as best effort.
> 
> Keep TX EQTR running by logging RX_FOM read failures and continuing.
> Make failed lanes deterministic by initializing each lane FOM to 0 before
> reading and only updating it when the DME read succeeds. This avoids
> propagating stale or uninitialized values into EQTR evaluation.
> 
> Also update the kerneldoc return description to match behavior: RX_FOM
> DME read failures are logged for debug visibility, while get_rx_fom()
> vops failures are still propagated to the caller.
> 
> Signed-off-by: Can Guo <can.guo@xxxxxxxxxxxxxxxx>

Reviewed-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>

- Mani

> ---
>  drivers/ufs/core/ufs-txeq.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufs-txeq.c b/drivers/ufs/core/ufs-txeq.c
> index 9dca0cd344b8..23a12e221d31 100644
> --- a/drivers/ufs/core/ufs-txeq.c
> +++ b/drivers/ufs/core/ufs-txeq.c
> @@ -482,7 +482,9 @@ static void ufshcd_evaluate_tx_eqtr_fom(struct ufs_hba *hba,
>   * @h_iter: host TX EQTR iterator data structure
>   * @d_iter: device TX EQTR iterator data structure
>   *
> - * Returns 0 on success, negative error code otherwise
> + * Returns 0 on success, negative error code if get_rx_fom vops fails.
> + * RX_FOM DME get failures are debug-logged and treated as 0 FOM for
> + * that lane.
>   */
>  static int ufshcd_get_rx_fom(struct ufs_hba *hba,
>  			     struct ufs_pa_layer_attr *pwr_mode,
> @@ -494,22 +496,30 @@ static int ufshcd_get_rx_fom(struct ufs_hba *hba,
>  
>  	/* Get FOM of host's TX lanes from device's RX_FOM. */
>  	for (lane = 0; lane < pwr_mode->lane_tx; lane++) {
> +		h_iter->fom[lane] = 0;
>  		ret = ufshcd_dme_peer_get(hba, UIC_ARG_MIB_SEL(RX_FOM,
>  					  UIC_ARG_MPHY_RX_GEN_SEL_INDEX(lane)),
>  					  &fom);
> -		if (ret)
> -			return ret;
> +		if (ret) {
> +			dev_dbg(hba->dev, "Failed to get FOM for Host TX Lane %d: %d\n",
> +				lane, ret);
> +			continue;
> +		}
>  
>  		h_iter->fom[lane] = (u8)fom;
>  	}
>  
>  	/* Get FOM of device's TX lanes from host's RX_FOM. */
>  	for (lane = 0; lane < pwr_mode->lane_rx; lane++) {
> +		d_iter->fom[lane] = 0;
>  		ret = ufshcd_dme_get(hba, UIC_ARG_MIB_SEL(RX_FOM,
>  				     UIC_ARG_MPHY_RX_GEN_SEL_INDEX(lane)),
>  				     &fom);
> -		if (ret)
> -			return ret;
> +		if (ret) {
> +			dev_dbg(hba->dev, "Failed to get FOM for Device TX Lane %d: %d\n",
> +				lane, ret);
> +			continue;
> +		}
>  
>  		d_iter->fom[lane] = (u8)fom;
>  	}
> -- 
> 2.34.1
> 

-- 
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