13 Apr, 2015

1 commit

  • Although some races in runtime PM refcount was fixed by the commit
    [664c715573c2: ALSA: hda - Work around races of power up/down with
    runtime PM], there is still a race in the following case:

    CPU0: CPU1 :
    runtime suspend:
    codec->in_pm = 1
    snd_hdac_power_up_pm():
    pm_runtime_get_sync() skipped
    suspend finished:
    codec->in_pm = 0
    snd_hdac_power_down_pm():
    pm_runtime_put_*() is called!

    For avoiding this situation, increment in_pm flag atomically when it's
    non-zero, and decrement accordingly, to ensure that in_pm is set
    consistently for the whole concurrent operations.

    Also, since atomic_inc_not_zero() and atomic_dec_if_positive() are
    lengthy inline functions, move snd_hdac_power_up_pm() and _down_pm()
    to sound/hda/hdac_device.c as no inline functions.

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     

08 Apr, 2015

1 commit

  • Currently, snd_hdac_power_up()/down() helpers checks whether the codec
    is being in pm (suspend/resume), and skips the call of runtime get/put
    during it. This is needed as there are lots of power up/down
    sequences called in the paths that are also used in the PM itself. An
    example is found in hda_codec.c::codec_exec_verb(), where this can
    power up the codec while it may be called again in its power up
    sequence, too.

    The above works in most cases, but sometimes we really want to wait
    for the real power up. For example, the control element get/put may
    want explicit power up so that the value change is assured to reach to
    the hardware. Using the current snd_hdac_power_up(), however,
    results in a race, e.g. when it's called during the runtime suspend is
    being performed. In the worst case, as found in patch_ca0132.c, it
    can even lead to the deadlock because the code assumes the power up
    while it was skipped due to the check above.

    For dealing with such cases, this patch makes snd_hdac_power_up() and
    _down() to two variants: with and without in_pm flag check. The
    version with pm flag check is named as snd_hdac_power_up_pm() while
    the version without pm flag check is still kept as
    snd_hdac_power_up(). (Just because the usage of the former is fewer.)

    Then finally, the patch replaces each call potentially done in PM with
    the new _pm() variant.

    In theory, we can implement a unified version -- if we can distinguish
    the current context whether it's in the pm path. But such an
    implementation is cumbersome, so leave the code like this a bit messy
    way for now...

    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96271
    Signed-off-by: Takashi Iwai

    Takashi Iwai
     

04 Apr, 2015

2 commits


23 Mar, 2015

7 commits

  • The amp hash table was used for recording the cached reads of some
    capability values like pin caps or amp caps. Now all these are moved
    to regmap as well.

    One addition to the regmap helper is codec->caps_overwriting flag.
    This is set in snd_hdac_override_parm(), and the regmap helper accepts
    any register while this flag is set, so that it can overwrite even the
    read-only verb like AC_VERB_PARAMETERS. The flag is cleared
    immediately in snd_hdac_override_parm(), as it's a once-off flag.

    Along with these changes, the no longer needed amp hash and relevant
    fields are removed from hda_codec struct now.

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • Sometimes we need the uncached reads, e.g. for refreshing the tree.
    This patch provides the helper function for that and uses it for
    refreshing widgets, reading subtrees and the whole proc reads.

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • Let's start converting the access functions to regmap.
    The first one is the simplest, just converting the codec parameter
    read helper function snd_hda_param_read().

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • When the driver is unloaded before the codec is bound, it still keeps
    the runtime PM refcount up, and results in the unbalance. This patch
    covers these cases by introducing a flag indicating the runtime PM
    initialization and handling the codec registration procedure more
    properly. It also fixes the missing input beep device as a gratis,
    too.

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • Add an overriding exec_verb op to struct hdac_device so that the call
    via snd_hdac_exec_verb() can switch to a different route depending on
    the setup. The codec driver sets this field so that it can handle the
    errors or applying quirks appropriately. Furthermore, this mechanism
    will be used for smooth transition for the regmap support in later
    patches.

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • This patch changes the sysfs files assigned to the codec device on the
    bus which were formerly identical with hwdep sysfs files. Now it
    shows only a few core parameter, vendor_id, subsystem_id, revision_id,
    afg, mfg, vendor_name and chip_name.

    In addition, now a widget tree is added to the bus device sysfs
    directory for showing the widget topology and attributes. It's just a
    flat tree consisting of subdirectories named as the widget NID
    including various attributes like widget capability bits. The AFG
    (usually NID 0x01) is always found there, and it contains always
    amp_in_caps, amp_out_caps and power_caps files. Each of these
    attributes show a single value. The rest are the widget nodes
    belonging to that AFG. Note that the child node might not start from
    0x02 but from another value like 0x0a.

    Each child node may contain caps, pin_caps, amp_in_caps, amp_out_caps,
    power_caps and connections files. The caps (representing the widget
    capability bits) always contain a value. The rest may contain
    value(s) if the attribute exists on the node. Only connections file
    show multiple values while other attributes have zero or one single
    value.

    An example of ls -R output is like below:
    % ls -R /sys/bus/hdaudio/devices/hdaudioC0D0/
    /sys/bus/hdaudio/devices/hdaudioC0D0/widgets/:
    01/ 04/ 07/ 0a/ 0d/ 10/ 13/ 16/ 19/ 1c/ 1f/ 22/
    02/ 05/ 08/ 0b/ 0e/ 11/ 14/ 17/ 1a/ 1d/ 20/ 23/
    03/ 06/ 09/ 0c/ 0f/ 12/ 15/ 18/ 1b/ 1e/ 21/

    /sys/bus/hdaudio/devices/hdaudioC0D0/widgets/01:
    amp_in_caps amp_out_caps power_caps

    /sys/bus/hdaudio/devices/hdaudioC0D0/widgets/02:
    amp_in_caps amp_out_caps caps connections pin_caps pin_cfg
    power_caps

    /sys/bus/hdaudio/devices/hdaudioC0D0/widgets/03:
    .....

    Signed-off-by: Takashi Iwai

    Takashi Iwai
     
  • Now some codes and functionalities of hda_codec struct are moved to
    hdac_device struct. A few basic attributes like the codec address,
    vendor ID number, FG numbers, etc are moved to hdac_device, and they
    are accessed like codec->core.addr. The basic verb exec functions are
    moved, too.

    Signed-off-by: Takashi Iwai

    Takashi Iwai