<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle20
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle21
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal">Hi All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m a gstreamer developer and is trying to implement a video display plugin based on DRM/KMS which is named “kmssink”.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I met a problem that the kmssink will have permission issue when running with x11 and wayland. Because these two window system will hold DRM-Master in their life time. So I’m change the code to use control node “controlD64” for display
and file node card0 for memory management. It work really well. Video can show on multi display with wayland and x11. But I notice that in the Linux kernel mainline, below commit remove the control node:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><b>commit 8a357d10043c75e980e7fcdb60d2b913491564af <o:p></o:p></b></p>
<p class="MsoNormal"><b>Author: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch"><span style="font-weight:normal">daniel.vetter@ffwll.ch</span></a>><o:p></o:p></b></p>
<p class="MsoNormal"><b>Date: Fri Oct 28 10:10:50 2016 +0200 <o:p></o:p></b></p>
<p class="MsoNormal"><b><o:p> </o:p></b></p>
<p class="MsoNormal"><b> drm: Nerf DRM_CONTROL nodes <o:p></o:p></b></p>
<p class="MsoNormal"><b> <o:p></o:p></b></p>
<p class="MsoNormal"><b> Looking at the ioctl permission checks I noticed that it's impossible
<o:p></o:p></b></p>
<p class="MsoNormal"><b> to import gem buffers into a control nodes, and fd2handle/handle2fd
<o:p></o:p></b></p>
<p class="MsoNormal"><b> also don't work, so no joy with dma-bufs. <o:p></o:p></b></p>
<p class="MsoNormal"><b> <o:p></o:p></b></p>
<p class="MsoNormal"><b> The only way to do anything with a control node is by drawing stuff
<o:p></o:p></b></p>
<p class="MsoNormal"><b> into a dumb buffer and displaying that. I suspect control nodes are an
<o:p></o:p></b></p>
<p class="MsoNormal"><b> entirely unused thing, and a cursory check shows that there does not
<o:p></o:p></b></p>
<p class="MsoNormal"><b> seem to be any callers of drmOpenControl nor of the other drmOpen
<o:p></o:p></b></p>
<p class="MsoNormal"><b> functions using DRM_MODE_CONTROL. <o:p></o:p></b></p>
<p class="MsoNormal"><b> <o:p></o:p></b></p>
<p class="MsoNormal"><b> Since I don't like dead uabi, let's remove it. But since this would be
<o:p></o:p></b></p>
<p class="MsoNormal"><b> a really big change I think it's better to start out small by simply
<o:p></o:p></b></p>
<p class="MsoNormal"><b> not registering anything. We can garbage-collect the dead code later
<o:p></o:p></b></p>
<p class="MsoNormal"><b> on, once we're sure it's really not used anywhere. <o:p>
</o:p></b></p>
<p class="MsoNormal"><b> <o:p></o:p></b></p>
<p class="MsoNormal"><b> Acked-by: Dave Airlie <<a href="mailto:airlied@gmail.com"><span style="font-weight:normal">airlied@gmail.com</span></a>><o:p></o:p></b></p>
<p class="MsoNormal"><b> Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@intel.com"><span style="font-weight:normal">daniel.vetter@intel.com</span></a>><o:p></o:p></b></p>
<p class="MsoNormal"><b> Link: <a href="http://patchwork.freedesktop.org/patch/msgid/20161028081050.1042-1-daniel.vetter@ffwll.ch">
<span style="font-weight:normal">http://patchwork.freedesktop.org/patch/msgid/20161028081050.1042-1-daniel.vetter@ffwll.ch</span></a><o:p></o:p></b></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This will have big impace on my case, and I cannot figure out how to fix this issue. I think control node is useful, actually many users are using this node for application development including rockchip and amlogic. details please refer
to: <a href="http://gstreamer-devel.966125.n4.nabble.com/Can-kmssink-run-with-x11-or-wayland-which-is-based-on-drm-kms-also-td4683783.html#a4683819">
http://gstreamer-devel.966125.n4.nabble.com/Can-kmssink-run-with-x11-or-wayland-which-is-based-on-drm-kms-also-td4683783.html#a4683819</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I‘m sending this mail for <b>require restoring control node in file system, or is there any other way to fix my permission issue</b>?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best wishes<o:p></o:p></p>
<p class="MsoNormal" style="line-height:150%"><span style="font-size:12.0pt;line-height:150%;color:#1F497D"><img border="0" width="288" height="2" style="width:3.0in;height:.0208in" id="Picture_x0020_3" src="cid:image001.png@01D311F5.7C86B8E0" alt="cid:image002.png@01D13808.32F8E040"></span><b><u><span style="font-size:12.0pt;line-height:150%;color:#1F497D"><o:p></o:p></span></u></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Haihua Hu<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">MPU Mulitmedia Software</span></b><b><u><span style="font-size:10.0pt;color:#1F497D"><o:p></o:p></span></u></b></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">NXP Semiconductors
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">No.288 ZhuYuan Road<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Suzhou New District 215011, P.R.C<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Phone: +86-512-680566738<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">jared.hu@nxp.com<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;color:#1F497D"><img border="0" width="288" height="49" style="width:3.0in;height:.5104in" id="Picture_x0020_9" src="cid:image002.png@01D311F5.7C86B8E0" alt="cid:image003.png@01D13808.32F8E040"></span><span style="font-size:12.0pt;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>