On Thursday 05 June 2008 23:24:05 Hannu Savolainen wrote:
> Hi all,
>
> There are some bugs in the current hdaudio driver that may cause empty
> groups. The driver will create a new group after adding 4 to 8 controls
> to the group. The purpose of this hack is to prevent the mixer screen
> from becoming too wide. Unfortunately the driver may after that figure
> out that none of the remaining controls are connected to anywhere. This
> will leave unused groups.
>
> One solution might be moving this logic to ossxmix. The driver will
> create just one group and ossxmix will break it to multiple "lines" if
> the current box is getting too wide. Would that be implementable?
I think this is implementable though not trivial:
1. Get width (I think this is related to gdk_screen_get_width (GTK >= 2.2), and
use some X function for other case?). I don't know if this works on more exotic
configurations (Xinerama?), but I suspect it does.
2. Check constantly in load_devinfo that adding a control won't get past the
width.
3. If so, decide to move/split group downward.
4. Gtk only has concept of Horizontal/Vertical boxes. We'll have to recreate
some of the box hierarchy in order to get it lower.
> The mixer API is developing to a direction where drivers can create
> empty groups in advance and the populate them later "on demand". This
> may cause problems if ossmix just throws away all groups it thinks are
> empty. It is acceptable if the group h/vboxes are not shown until
> something is created inside them.
At the moment, the only way I know of to discover whether new control have been
added with the current API is to poll the device for total number of mixers
(via SNDCTL_MIX_NREXT) and to compare this to the previous number (this is what
ossxmix does for VMIX). If so, than the groups may be ignored/throwed away and
it won't matter.
(BTW, If controls can also be removed, and not just added, than there's an edge
case:
A. Total number can be the same even in a case of change. (1-1=0)
B. ossxmix polls the controls, if all the newly added mixers have the same
control numbers than get_value won't fail and the display won't be reloaded.
Not sure how to really fix this: A separate flag in SNDCTL_MIXERINFO to inform
of such changes? Or maybe changing a group's modify_counter in
SNDCTL_MIX_EXTINFO?)
Yours,
Yair K.
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