Re: [PATCH] mmc: sdhci: ignore 3.3v voltage switch if ios.vdd is 0

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Adrian,

On 08/02/2017 12:28 AM, Adrian Hunter wrote:
On 02/08/17 02:58, Zhoujie Wu wrote:
One issue was found on a removable high speed sd card with
runtime pm enabled.
When SD card is unplugged, it keep printing "Switching to 3.3V
signalling voltage failed".
And found below sequence triggers the error.

mmc_rescan
	-> mmc_sd_detect
		-> mmc_power_off  -- mmc->ios.vdd is update to 0.
	-> mmc_claim_host
		-> sdhci_runtime_resume_host
			-> sdhci_start_signal_voltage_switch
We ought to be able to skip restoring the I/O state when the power is off i.e.:

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index cf2166e4190d..4a70f2f765b6 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2934,7 +2934,8 @@ int sdhci_runtime_resume_host(struct sdhci_host *host)

  	sdhci_init(host, 0);

-	if (mmc->ios.power_mode != MMC_POWER_UNDEFINED) {
+	if (mmc->ios.power_mode != MMC_POWER_UNDEFINED &&
+	    mmc->ios.power_mode != MMC_POWER_OFF) {
  		/* Force clock and power re-program */
  		host->pwr = 0;
  		host->clock = 0;

Your suggestion works and better than mine. I will do more tests and update the patch later. thanks.


				-> mmc_regulator_set_vqmmc
					-> mmc_ocrbitnum_to_vdd

When mmc_ocrbitnum_to_vdd is called, the mmc->ios.vdd is 0, so it
always return -EINVAL. The signal switch will always fail and
print out warning.

Signed-off-by: Zhoujie Wu <zjwu@xxxxxxxxxxx>
---
Hi Ulf,
	Not sure if this is the best way to fix it. Please help to suggest. Thanks.

  drivers/mmc/host/sdhci.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ecd0d43..011ebbe 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1878,7 +1878,7 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
  		ctrl &= ~SDHCI_CTRL_VDD_180;
  		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
- if (!IS_ERR(mmc->supply.vqmmc)) {
+		if ((!IS_ERR(mmc->supply.vqmmc)) && mmc->ios.vdd) {
  			ret = mmc_regulator_set_vqmmc(mmc, ios);
  			if (ret) {
  				pr_warn("%s: Switching to 3.3V signalling voltage failed\n",


--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux USB Devel]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux