Two times out of 2000 reboots I ran into the error message
"rockchip_emmc_phy_power: dllrdy timeout". Presumably there is some
corner case where the DLL just takes a little longer to timeout. Let's
give it even more time to handle these corner cases.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
drivers/phy/phy-rockchip-emmc.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/phy/phy-rockchip-emmc.c b/drivers/phy/phy-rockchip-emmc.c
index a2aa6aca7dec..fd57345ffed2 100644
--- a/drivers/phy/phy-rockchip-emmc.c
+++ b/drivers/phy/phy-rockchip-emmc.c
@@ -206,8 +206,18 @@ static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
* per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
* Hopefully we won't be running at 100 kHz, but we should still make
* sure we wait long enough.
+ *
+ * NOTE: There appear to be corner cases where the DLL seems to take
+ * extra long to lock for reasons that aren't understood. In some
+ * extreme cases we've seen it take up to over 10ms (!). We'll be
+ * generous and give it 50ms. We still busy wait here because:
+ * - In most cases it should be super fast.
+ * - This is not called lots during normal operation so it shouldn't
+ * be a power or performance problem to busy wait. We expect it
+ * only at boot / resume. In both cases, eMMC is probably on the
+ * critical path so busy waiting a little extra time should be OK.
*/
- timeout = jiffies + msecs_to_jiffies(10);
+ timeout = jiffies + msecs_to_jiffies(50);
do {
udelay(1);
--
2.8.0.rc3.226.g39d4020
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