On Thu, 2010-07-01 at 14:28 +0200, ext Taneja, Archit wrote:
> > On Thu, 2010-07-01 at 12:31 +0200, ext Archit Taneja wrote:
> > > From: Sumit Semwal <sumit.semwal@xxxxxx>
> > >
> > > 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.
If the DSS sysfs code if broken, let's rather fix it than name the
manager with a rather strange name, just to circumvent a bug.
>
> In my opinion, len should be calculated as:
>
> len = max(len, strlen(mgr->name));
>
> This way strncmp would work correctly in all the cases.
sysfs_streq() could be used there.
Tomi
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