After suspend/resume all of the dw_mmc registers are reset to defaults. We restore most of them, but specifically don't setup the clock registers after resume unless we've got a powered card. Things still work because the core will eventually call set_ios() and we'll set things up.
There doesn't seem to be any reason that I can see _not_ to set things up after resume. Restoring this state makes the code easier to reason about and should help prevent bugs. It also allows us to do a register dump before and after suspend/resume to confirm that we've set things up OK. I examined the state of the dw_mmc instance before and after suspend after this patch. I had no card inserted in an SD card slot. Before this patch, differences were: * CLKDIV (0x08) * CLKENA (0x10) * TMOUT (0x14) * CMD (0x2C) - difference is not important * CLKSEL (0x9C - exynos specific) After this patch, only TMOUT was different. I have a separate patch for that. Signed-off-by: Doug Anderson <diand...@chromium.org> Reviewed-by: Tomasz Figa <t.f...@samsung.com> --- Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None drivers/mmc/host/dw_mmc.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index e614b03..3d1ee2d 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -2522,9 +2522,7 @@ int dw_mci_resume(struct dw_mci *host) struct dw_mci_slot *slot = host->slot[i]; if (!slot) continue; - if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER) { - dw_mci_set_ios(slot->mmc, &slot->mmc->ios); - } + dw_mci_set_ios(slot->mmc, &slot->mmc->ios); ret = mmc_resume_host(host->slot[i]->mmc); if (ret < 0) -- 1.8.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/