mmc: sdhci: Fix read-only detection with JMicron 388 chip

On HP laptops with JMicron 388 chip, the write-locked SD card isn't
detected correctly as read-only in many cases.  This is because the
PRESENT_STATE register becomes unsable just after plugging, and it
returns the WRITE_PROTECT bit wrongly at the first read.

This patch fixes the read-only detection by adding a new sdhci quirk
indicating to check the register more intensively with a relatively
long delay.

The patch is tested with 2.6.39-rc4 kernel.

Cc: Aries Lee <arieslee@jmicron.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 83bd9f76709a..92e1c9ad126c 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -85,6 +85,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK_NO_HISPD_BIT                        (1<<29)
 /* Controller treats ADMA descriptors with length 0000h incorrectly */
 #define SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC            (1<<30)
+/* The read-only detection via SDHCI_PRESENT_STATE register is unstable */
+#define SDHCI_QUIRK_UNSTABLE_RO_DETECT                  (1<<31)
 
         int irq;                /* Device IRQ */
         void __iomem *ioaddr;   /* Mapped address */