[Mesa-dev] [PATCH] gbm: dlopen libglapi so gbm_create_device works

[Frank Henigman]

On Sat, Nov 8, 2014 at 7:13 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 06/11/14 21:29, Frank Henigman wrote:
>> From: Frank Henigman <fjhenigman at chromium.org>
>>
>> Dri driver libs are not linked to pull in libglapi so gbm_create_device()
>> fails when it tries to dlopen them (unless the application is linked
>> with something that does pull in libglapi, like libGL).
>> Until dri drivers can be fixed properly, dlopen libglapi before trying
>> to dlopen them.
>> https://bugs.freedesktop.org/show_bug.cgi?id=57702
>>
> Hi Frank,
>
> I think I can understand the frustration that this has caused you, so
> unless there are any objections I will gladly pick it up for the 10.4
> (and if there are no side effects for the stable 10.3 branch).
>
> Just a couple of nits, which I'm planning to make prior to pushing this
> (a week from now, just before the branchpoint)
>  * the bugzilla report mentiones libglapi, but in a different light so
> I'll rephase the commit msg a bit.
>  * we might as well print out an error message and bail out when we
> dlopen fails.

I think the check should be after the dlopen() of blah_dri.so, a few lines down,
and show the dlerror() message if that fails.  That's the code I've
put in in the
past to diagnose this issue, and I really should have included it in my patch.
Then there's probably no need to error check the new dlopen, and the later
check can stay in when the new dlopen is removed.
Thanks!

> Thanks for bringing this up :)
>
> -Emil
>
>> Signed-off-by: Frank Henigman <fjhenigman at google.com>
>> ---
>>  src/gbm/backends/dri/gbm_dri.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
>> index f637e32..6ea2294 100644
>> --- a/src/gbm/backends/dri/gbm_dri.c
>> +++ b/src/gbm/backends/dri/gbm_dri.c
>> @@ -311,6 +311,11 @@ dri_open_driver(struct gbm_dri_device *dri)
>>     if (search_paths == NULL)
>>        search_paths = DEFAULT_DRIVER_DIR;
>>
>> +   /* Temporarily work around dri driver libs that need symbols in libglapi
>> +    * but don't automatically link it in.
>> +    */
>> +   dlopen("libglapi.so.0", RTLD_LAZY | RTLD_GLOBAL);
>> +
>>     dri->driver = NULL;
>>     end = search_paths + strlen(search_paths);
>>     for (p = search_paths; p < end && dri->driver == NULL; p = next + 1) {
>>
>