From f595e8e77a51eee35e331f69321766593a845ef2 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 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 --- 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 605be55f8d2d0..e3bf901b10aaf 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -3836,6 +3836,7 @@ 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)); -- 2.47.3