diff options
| author | Takashi Iwai <tiwai@suse.de> | 2011-04-21 20:26:38 +0200 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2011-05-24 21:02:42 -0400 |
| commit | 82b0e23a295cc58d1290017ee97a40956ad68d94 (patch) | |
| tree | f3f140be979623ae8b83b79841eb842858ed054b /drivers/mmc/host/sdhci.c | |
| parent | f06c9153f5ecd47dfed23f87b9d08e42ff0e4170 (diff) | |
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>
Diffstat (limited to 'drivers/mmc/host/sdhci.c')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index a70a3d1ef35a..e5cfe70dc23b 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1256,14 +1256,11 @@ out: spin_unlock_irqrestore(&host->lock, flags); } -static int sdhci_get_ro(struct mmc_host *mmc) +static int check_ro(struct sdhci_host *host) { - struct sdhci_host *host; unsigned long flags; int is_readonly; - host = mmc_priv(mmc); - spin_lock_irqsave(&host->lock, flags); if (host->flags & SDHCI_DEVICE_DEAD) @@ -1281,6 +1278,29 @@ static int sdhci_get_ro(struct mmc_host *mmc) !is_readonly : is_readonly; } +#define SAMPLE_COUNT 5 + +static int sdhci_get_ro(struct mmc_host *mmc) +{ + struct sdhci_host *host; + int i, ro_count; + + host = mmc_priv(mmc); + + if (!(host->quirks & SDHCI_QUIRK_UNSTABLE_RO_DETECT)) + return check_ro(host); + + ro_count = 0; + for (i = 0; i < SAMPLE_COUNT; i++) { + if (check_ro(host)) { + if (++ro_count > SAMPLE_COUNT / 2) + return 1; + } + msleep(30); + } + return 0; +} + static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable) { struct sdhci_host *host; |