On Thu, 2012-08-30 at 17:10 +0530, Archit Taneja wrote: > The display sysfs attribute's store function needs to be changed with the > introduction of outputs. > > Providing a manager to the display isn't enough to create a link now, the > manager needs and output to connect to. A manager's display store file only > has the information of the manager and the desired display, it is not aware > of which output should the manager connect to. > > Because of this, a new constraint needs to be set up when setting a display > via > this sysfs file. The constraint is that the desired display should already be > connected to an output before calling this sysfs function. > > This might break some existing user space stuff which uses sysfs directly. But > in most cases dss_recheck_connections will connect displays to floating > outputs. > DSS sysfs files are being planned to be remove anyway, so it's not much of a > harm. > > Signed-off-by: Archit Taneja <[email protected]> > --- > drivers/video/omap2/dss/manager.c | 25 ++++++++++++++++++++----- > 1 file changed, 20 insertions(+), 5 deletions(-) > > diff --git a/drivers/video/omap2/dss/manager.c > b/drivers/video/omap2/dss/manager.c > index fd39f66..d808ce2 100644 > --- a/drivers/video/omap2/dss/manager.c > +++ b/drivers/video/omap2/dss/manager.c > @@ -74,18 +74,33 @@ static ssize_t manager_display_store(struct > omap_overlay_manager *mgr, > if (dssdev) > DSSDBG("display %s found\n", dssdev->name); > > - if (mgr->get_device(mgr)) { > - r = mgr->unset_device(mgr); > + if (mgr->output) { > + if (mgr->output->device) { > + r = mgr->output->unset_device(mgr->output); > + if (r) { > + goto put_device; > + DSSERR("failed to unset device from output\n"); > + } > + } > + > + r = mgr->unset_output(mgr); > if (r) { > - DSSERR("failed to unset display\n"); > + DSSERR("failed to unset current output\n"); > goto put_device; > } > } > > if (dssdev) { > - r = mgr->set_device(mgr, dssdev); > + struct omap_dss_output *out = dssdev->output; > + > + if (!out) { > + DSSERR("no output connected to device\n"); > + goto put_device; > + } > + > + r = mgr->set_output(mgr, out); > if (r) { > - DSSERR("failed to set manager\n"); > + DSSERR("failed to set manager output\n"); > goto put_device; > } >
Hmm, I think this is a bit broken. If I read this right, the unlinking removes both mgr-output link and the output-dssdev link. But the linking part only sets up the mgr-output link. So if there's a very simple configuration with one display, if you unlink it via sysfs you can't link it back again. The store function gets the mgr and the dssdev as arguments. I think this could be changed so that the function would "guess" the needed output. Well, not so much a guess, because a dssdev can only be connected to one output, defined by the HW design. That is basically what the recheck_connections does, we could use the same method here. Then this sysfs file should work just like before. Tomi
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