Link to open tickets only: we're investigating more and need more test results

wiki/src/support/known_issues/graphics.mdwn

@@ -131,6 +131,8 @@ Tickets: #11095 #12482
 For some models, adding `radeon.modeset=0` to the
 [[startup options|/doc/first_steps/startup_options/#boot_loader_menu]] fixes the issue.
 
+We need more test results from users: [[!tails_ticket 12482]]
+
 <a id="radeon-r9"></a>
 
 AMD Radeon R9
@@ -227,6 +229,8 @@ cards.
 Otherwise, try adding `nouveau.noaccel=1` or `nouveau.modeset=0` to the
 [[startup options|doc/first_steps/startup_options#boot_loader_menu]].
 
+We need more test results from users: [[!tails_ticket 15116]]
+
 <a id="nvidia-pascal"></a>
 
 NVIDIA Pascal