[media] rc: nuvoton: fix hang if chip is configured for alternative EFM IO address

If a system configures the Nuvoton chip to use the alternative
EFM IO address (CR_EFIR2) then after probing the primary EFM IO
address (CR_EFIR) this region is not released.

If a driver for another function of the Nuvoton Super I/O
chip uses the same probing mechanism then it will hang if
loaded after the nuvoton-cir driver.
This was reported for the nct6775 hwmon driver.

Fix this by properly releasing the region after probing CR_EFIR.
This regression was introduced with kernel 4.6 so cc it to stable.

Reported-by: Antti Seppälä <a.seppala@gmail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Antti Seppälä <a.seppala@gmail.com>
Cc: <stable@vger.kernel.org> # 4.6.x-
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/rc/nuvoton-cir.c b/drivers/media/rc/nuvoton-cir.c
index 36abfc2800f03d88faf2bb195cdf247a6d4207ec..00215f3438196b38dc0cc7b47363ab3814ee32ca 100644 (file)
--- a/drivers/media/rc/nuvoton-cir.c
+++ b/drivers/media/rc/nuvoton-cir.c
@@ -393,6 +393,7 @@ static int nvt_hw_detect(struct nvt_dev *nvt)
        /* Check if we're wired for the alternate EFER setup */
        nvt->chip_major = nvt_cr_read(nvt, CR_CHIP_ID_HI);
        if (nvt->chip_major == 0xff) {
+               nvt_efm_disable(nvt);
                nvt->cr_efir = CR_EFIR2;
                nvt->cr_efdr = CR_EFDR2;
                nvt_efm_enable(nvt);