RE: [PATCH] mmc: sdhci-pci-gli: Fail runtime resume on PLL timeout

[BenChuang[莊智量]]

> -----Original Message-----
> From: Pengpeng Hou <hppiscas@xxxxxxx>
> Sent: Sunday, September 6, 2026 11:40 AM
> To: Adrian Hunter <adrian.hunter@xxxxxxxxx>; Ulf Hansson <ulfh@xxxxxxxxxx>
> Cc: Pengpeng Hou <hppiscas@xxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx; BenChuang[莊智量]
> <Ben.Chuang@xxxxxxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] mmc: sdhci-pci-gli: Fail runtime resume on PLL timeout
>
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>
> gl9763e_runtime_resume() logs when the internal clock never becomes
> stable but still enables the card clock and reports runtime-resume
> success.
>
> Return the poll timeout before enabling the card clock. Clear the
> PLL-enable bit so a failed resume leaves the clock state matching runtime
> suspend. Low-power negotiation remains enabled for the suspended device.
>
> The issue was found by our static-analysis tool and manually reviewed.
>

Hi Pengpeng,

Thanks for the patch.

Recently, no new Chromebooks use the GL9763E chip. This driver is old and we only want to keep it stable.

This modification comes from a static-analysis tool, not a real bug report from a user. On our side, we only
have the generic EVB board and we do not have the real Chromebook machines to test this change.
Changing the return value from 0 to a non-zero error like -ETIMEOUT might bring unknown risks to old machines,
so we think it is safer to keep the original code.

At this stage, we want to see what the maintainers think about this. Thanks!

Best regards,
Ben Chuang

> Fixes: d607667bb8fa ("mmc: sdhci-pci-gli: Add runtime PM for GL9763E")
> Assisted-by: gpt 5
> Signed-off-by: Pengpeng Hou <hppiscas@xxxxxxx>
> ---
>  drivers/mmc/host/sdhci-pci-gli.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
> index b55618566d65..17717b54e08c 100644
> --- a/drivers/mmc/host/sdhci-pci-gli.c
> +++ b/drivers/mmc/host/sdhci-pci-gli.c
> @@ -1888,6 +1888,7 @@ static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip)
>         struct sdhci_pci_slot *slot = chip->slots[0];
>         struct sdhci_host *host = slot->host;
>         u16 clock;
> +       int ret;
>
>         if (host->mmc->ios.power_mode != MMC_POWER_ON)
>                 return 0;
> @@ -1899,11 +1900,18 @@ static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip)
>         sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
>
>         /* Wait max 150 ms */
> -       if (read_poll_timeout(sdhci_readw, clock, (clock & SDHCI_CLOCK_INT_STABLE),
> -                             1000, 150000, false, host, SDHCI_CLOCK_CONTROL)) {
> +       ret = read_poll_timeout(sdhci_readw, clock,
> +                               (clock & SDHCI_CLOCK_INT_STABLE),
> +                               1000, 150000, false, host,
> +                               SDHCI_CLOCK_CONTROL);
> +       if (ret) {
>                 pr_err("%s: PLL clock never stabilised.\n",
>                        mmc_hostname(host->mmc));
>                 sdhci_dumpregs(host);
> +
> +               clock &= ~SDHCI_CLOCK_PLL_EN;
> +               sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
> +               return ret;
>         }
>
>         clock |= SDHCI_CLOCK_CARD_EN;
> --
> 2.50.1 (Apple Git-155)

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