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From: Frank Li <Frank.Li@nxp.com>
To: adrian.hunter@intel.com, ulf.hansson@linaro.org, haibo.chen@nxp.com
Cc: Frank Li <frank.li@nxp.com>,
	Frank.Li@nxp.com, s.hauer@pengutronix.de, kernel@pengutronix.de,
	festevam@gmail.com, imx@lists.linux.dev,
	linux-mmc@vger.kernel.org, s32@nxp.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/4] mmc: sdhci: fix timing selection for 1-bit bus width
Date: Tue,  3 Mar 2026 16:00:58 -0500	[thread overview]
Message-ID: <20260303210131.2966214-3-Frank.Li@nxp.com> (raw)
In-Reply-To: <20260303105006.989339-2-ziniu.wang_1@nxp.com>

From: Frank Li (AI-BOT) <frank.li@nxp.com>

Subject: Re: [PATCH v2 1/4] mmc: sdhci: fix timing selection for 1-bit bus width

> -	if (!(host->quirks & SDHCI_QUIRK_FORCE_1_BIT_DATA))
> +	if (host->quirks & SDHCI_QUIRK_FORCE_1_BIT_DATA) {
> +		host->caps1 &= ~(SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 |
> +				 SDHCI_SUPPORT_DDR50 | SDHCI_SUPPORT_HS400);
> +		mmc->caps2 &= ~(MMC_CAP2_HS200 | MMC_CAP2_HS400 | MMC_CAP2_HS400_ES);
> +		mmc->caps &= ~(MMC_CAP_DDR | MMC_CAP_UHS);
> +	} else {
>  		mmc->caps |= MMC_CAP_4_BIT_DATA;
> +	}

The logic inversion here is correct and the fix addresses the root cause
per JEDEC spec. However, consider whether clearing MMC_CAP_UHS is
necessary—UHS modes require 4-bit width anyway, so this may be redundant
with the SDR104/SDR50/DDR50 clears. If intentional for belt-and-suspenders
safety, add a brief comment explaining why.

Also verify that mmc pointer is always valid at this point in
sdhci_setup_host(). If there's any path where mmc could be NULL, the
new code will crash.

AI bot review and may be useless.

  reply	other threads:[~2026-03-03 21:02 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-03 10:50 [PATCH v2 0/4] mmc: sdhci-esdhc-imx: add 1-bit bus width support ziniu.wang_1
2026-03-03 10:50 ` [PATCH v2 1/4] mmc: sdhci: fix timing selection for 1-bit bus width ziniu.wang_1
2026-03-03 21:00   ` Frank Li [this message]
2026-03-11  9:05   ` Adrian Hunter
2026-03-11  9:19     ` [EXT] " Luke Wang
2026-03-03 10:50 ` [PATCH v2 2/4] mmc: sdhci-esdhc-imx: add 1-bit bus width support ziniu.wang_1
2026-03-03 21:00   ` Frank Li
2026-03-11  9:05   ` Adrian Hunter
2026-03-03 10:50 ` [PATCH v2 3/4] mmc: sdhci-esdhc-imx: remove duplicate HS400 bus width validation ziniu.wang_1
2026-03-03 21:01   ` Frank Li
2026-03-11  9:05   ` Adrian Hunter
2026-03-03 10:50 ` [PATCH v2 4/4] mmc: sdhci-pltfm: remove duplicate DTS property parsing ziniu.wang_1
2026-03-03 21:01   ` Frank Li
2026-03-11  9:08   ` Adrian Hunter

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