From d3f0b8739e8a9ad22e227a74fac50f044fb4d7bb Mon Sep 17 00:00:00 2001 From: Jisheng Zhang Date: Sun, 24 May 2026 10:34:55 +0800 Subject: [PATCH] mmc: sdhci: add signal voltage switch in sdhci_resume_host commit f595e8e77a51eee35e331f69321766593a845ef2 upstream. I met one suspend/resume issue with sdr104 capable sdio wifi card (with "keep-power-in-suspend" set in DT property): After resuming from suspend to ram, the sdio wifi card stops working. Further debug shows that although ios shows the sdio card is at sdr104 mode, the voltage is still at 3V3. This is due to missing the calling of ->start_signal_voltage_switch() in sdhci_resume_host(). Fix this issue by adding ->start_signal_voltage_switch() in sdhci_resume_host(). This also matches what we do for sdhci_runtime_resume_host(). Then the question is: why this issue hasn't reported and fixed for so long time. IMHO, several reasons: Some host controllers just kick off the runtime resume for system resume, so they benefit from the well supported runtime pm code; Some platforms just use the old sdio wifi card which doesn't need signal voltage switch at all, the default voltage is 3v3 after resuming. Fixes: 6308d2905bd3 ("mmc: sdhci: add quirk for keeping card power during suspend") Signed-off-by: Jisheng Zhang Acked-by: Adrian Hunter Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/host/sdhci.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 285c73e6b196..86367723d155 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -3760,6 +3760,7 @@ int sdhci_resume_host(struct sdhci_host *host) host->pwr = 0; host->clock = 0; host->reinit_uhs = true; + mmc->ops->start_signal_voltage_switch(mmc, &mmc->ios); mmc->ops->set_ios(mmc, &mmc->ios); } else { sdhci_init(host, (mmc->pm_flags & MMC_PM_KEEP_POWER));