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    Subject[PATCH v2] applesmc: add sysfs file to report OSK
    The AppleSMC contains two char[32] keys, OSK0 and OSK1, which are not
    reported in the key count and index by default. These keys are used by
    the OS X boot sequence, and normally don't matter when running Linux.

    This patch creates a sysfs entry which reports the value of these keys
    as an ASCII string, to help emulators (such as QEMU) load OS X when
    running on genuine Apple hardware.

    Signed-off-by: Gabriel L. Somlo <somlo@cmu.edu>
    ---

    Henrik,

    On Mon, Dec 10, 2012 at 09:19:51PM +0100, Alexander Graf wrote:
    >
    > On Mon, Dec 10, 2012 at 08:54:14PM +0100, Henrik Rydberg wrote:
    > >
    > > The OSK string seems constant accross machines, which renders the
    > > patch rather pointless, no? And even if the OSK differs between a
    > > couple of machines, the emulator could easily handle it gracefully.
    >
    > The point is that the return value of the OSK is a copyrighted string,
    > we can not include in any other layer. The only way to make this
    > legally savvy is to read the key from the host.

    I believe this second version addresses your stylistic objections.

    As Alex pointed out, hardcoding the OSK in any open-source project
    might lead to legal/copyright related issues, whereas simply reporting
    whatever the the hardware happens to contain should keep everyone safe.

    As for struct applesmc_node_group info_group[]:

    > > Unfortunately this is not a good place to put random things going
    > > forward.

    I figured "info_group" for the "least bad" place to put the OSK, given
    that it's more or less "information from/about the SMC". If you could be
    persuaded by the above arguments to accept the patch, and have a better
    place in mind, I'd be happy to move it there...

    Thanks again,
    Gabriel

    drivers/hwmon/applesmc.c | 19 +++++++++++++++++++
    1 files changed, 19 insertions(+), 0 deletions(-)

    diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
    index b41baff..b37b271 100644
    --- a/drivers/hwmon/applesmc.c
    +++ b/drivers/hwmon/applesmc.c
    @@ -1013,6 +1013,24 @@ static ssize_t applesmc_key_at_index_store(struct device *dev,
    return count;
    }

    +static ssize_t applesmc_osk_show(struct device *dev,
    + struct device_attribute *attr, char *sysfsbuf)
    +{
    + int ret;
    + char buf[65];
    +
    + mutex_lock(&smcreg.mutex);
    + ret = read_smc(APPLESMC_READ_CMD, "OSK0", buf, 32);
    + if (!ret)
    + ret = read_smc(APPLESMC_READ_CMD, "OSK1", buf + 32, 32);
    + mutex_unlock(&smcreg.mutex);
    + if (ret)
    + return ret;
    +
    + buf[64] = '\0';
    + return snprintf(sysfsbuf, PAGE_SIZE, "%s\n", buf);
    +}
    +
    static struct led_classdev applesmc_backlight = {
    .name = "smc::kbd_backlight",
    .default_trigger = "nand-disk",
    @@ -1027,6 +1045,7 @@ static struct applesmc_node_group info_group[] = {
    { "key_at_index_type", applesmc_key_at_index_type_show },
    { "key_at_index_data_length", applesmc_key_at_index_data_length_show },
    { "key_at_index_data", applesmc_key_at_index_read_show },
    + { "osk", applesmc_osk_show },
    { }
    };

    --
    1.7.7.6


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