Hi,

On Thu, Jan 14, 2016 at 05:25:49PM +0000, Russell King - ARM Linux wrote:

On Thu, Jan 14, 2016 at 01:07:06PM +0100, Sebastian Reichel wrote:

quoted

On Thu, Jan 14, 2016 at 02:45:20PM +0530, Kishon Vijay Abraham I wrote:

quoted

Since v4.3+, CONFIG_REGULATOR_PBIAS should be enabled (for platforms that
have PBIAS regulator) in order for MMC1 to work.

Add a more verbose print to help enable CONFIG_REGULATOR_PBIAS for users
using a olddefconfig or a custom .config.

Signed-off-by: Kishon Vijay Abraham I <redacted>
---
 drivers/mmc/host/omap_hsmmc.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 7fb0753..7086bd6 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c

@@ -503,8 +503,11 @@ static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
 	host->pbias = devm_regulator_get_optional(host->dev, "pbias");
 	if (IS_ERR(host->pbias)) {
 		ret = PTR_ERR(host->pbias);
-		if ((ret != -ENODEV) && host->dev->of_node)
+		if ((ret != -ENODEV) && host->dev->of_node) {
+			dev_err(host->dev,
+			"SD card detect fail? enable CONFIG_REGULATOR_PBIAS\n");
 			return ret;
+		}
 		dev_dbg(host->dev, "unable to get pbias regulator %ld\n",
 			PTR_ERR(host->pbias));
 		host->pbias = NULL;

Is there a good reason against adding "depends on REGULATOR_PBIAS"
to MMC_OMAP_HS?

There are very good reasons not to do this: that will result in
configurations where MMC_OMAP_HS was set but without REGULATOR_PBIAS
ending up with MMC_OMAP_HS being disabled.  That doesn't help the
root problem, which is "why has the kernel boot regressed for my
previous working configuration?"

The solution proposed here adds a message to the boot which points
out fair and square what needs to be done to rectify the boot
failure.  Adding a dependency just brings up the question "where
has my MMC driver gone?"

The best thing would be to have no regression. Just printing a
message means I have to build another kernel. But more importantly
the message may not be visible by the user - e.g. if the display has
not yet been initialized.

-- Sebastian
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