> On Thu, 2010-07-01 at 12:31 +0200, ext Archit Taneja wrote:
> > From: Sumit Semwal <[email protected]>
> >
> > The addition of the new 2lcd manager requires modifications in the
> > dss_recheck_connections patch, this function behaves the
> same if the
> > 2lcd manager doesn't exist
>
> Here (and also in the previous patch) you talk about 2lcd,
> but the code uses lcd2.
Archit: The new manager's name defined in manager.c is 2lcd,
The channel's name in the enum is OMAP_DSS_CHANNEL_LCD2, and
the overlay manager enum is OMAP_DSS_OVL_MGR_LCD2.
2lcd as the manager name was taken so that no one makes mistakes
while reading/writing sysfs entries.
Also, in the dss2 code we use strncmp() to compare the manager
names in overlay_manager_store(). Now, if we name the new manager
as "lcd2", consider the following scenario:
Suppose an overlay has its manager presently set as "lcd2". Now
someone does a sysfs entry to make the manager as "lcd". So in this
case the variable buf is "lcd" and and mgr->name is "lcd2". The
variable len is calculated on the basis of buf ("lcd") as 3.
So strncmp just compares the first 3 chars, and in that case "lcd"
and "lcd2" are the same, luckily this doesn't cause an issue as the
first manager fetched by omap_dss_get_overlay_manager() is "lcd". If
the manager_list was filled in some other way then this would have
resulted an issue.
In my opinion, len should be calculated as:
len = max(len, strlen(mgr->name));
This way strncmp would work correctly in all the cases.
In order to take no risks, we named it as "2lcd".
Thanks,
Archit
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