Bug 113637 – [EFL] Get rid of --tiled-backing-store flag. Create and use --accelerated-composition instead.

• Status: RESOLVED
• Resolution: INVALID
• Component: WebKit EFL

[Ed Bartosh]

Copied from here: https://lists.webkit.org/pipermail/webkit-efl/2013-March/000536.html

  "tiled-backing-store" is a misused flag in this case
and, IMHO, "accelerated compositing" switch should be used in this case.
This flag was used because of "historical" reasons and it might be a good
time to fix it also .

  Also, --no-tiled-backing-store works as a workaround because it is
switches off texture mapper based accelerated compositing drawing which
uses opengl by default and because of this needs GLX . But texture mapper
has fallback mode when it uses ImageBuffer as a "texture" . To enable this
creating of EvasGLContext should be disabled. I remember Yael was fixing
it. IMHO, it would be better workaround for the Xvfb GLX regression.

[Ed Bartosh]

As far as I can see from the EwkView.cpp code(see below) EvasGLContext::create is not called when accelerated composition is off. It was fixed in my previous patch https://bug-113627-attachments.webkit.org/attachment.cgi?id=195820

Have I understood correctly that this is enough to get rid of --tiled-backing-store flag and introduce new flag --accelerated-compositing?

> git blame --date=short -L'278,289' WebKit2/UIProcess/API/efl/EwkView.cpp 
95177455 ([e-mail] 2013-03-19 278)     webView()-a>setEwkView(this);
02c57c8c (Ed Bartosh                   2013-03-30 279) #if USE(ACCELERATED_COMPOSITING)
61a77905 ([e-mail]           2013-02-13 280)     m_evasGL = adoptPtr(evas_gl_new(evas_object_evas_get(m_evasObject)));
61a77905 ([e-mail]           2013-02-13 281)     if (m_evasGL)
61a77905 ([e-mail]           2013-02-13 282)         m_evasGLContext = EvasGLContext::create(m_evasGL.get());
61a77905 ([e-mail]           2013-02-13 283) 
61a77905 ([e-mail]           2013-02-13 284)     if (!m_evasGLContext) {
61a77905 ([e-mail]           2013-02-13 285)         WARN("Failed to create Evas_GL, falling back to software mode.");
61a77905 ([e-mail]           2013-02-13 286)         m_isAccelerated = false;
61a77905 ([e-mail]           2013-02-13 287)     }
02c57c8c (Ed Bartosh                   2013-03-30 288) #endif
8d826648 ([e-mail]           2013-02-05 289)     WKViewInitialize(wkView());

[Ed Bartosh]

I think I misunderstood the task. Looking at WebCore/page/Frame.{cpp,h} I can see   tiled backing store-related code. So, the feature is actually used. Slava, can you elaborate a bit? In which part of the code tiled backing store used as a workeround and should be replaced by using accelerated compositing?

[Ed Bartosh]

No responce from the author of the idea. Closing as invalid.

[Viatcheslav Ostapenko]

(In reply to comment #3)
> No responce from the author of the idea. Closing as invalid.

I'm sorry, I missed this bug.
But it is invalid in any case as it proposed here.
We don't want to get rid of --tiled-backing-store flag.
And there was --accelerated-compositing flag, but it was removed because most ports don't work currently without it (especially WK2).
I meant that EFL port uses tiled backing store flag to switch off AC and it is not right, because tiled backing store itself can be used for single layer configuration (no AC).

Also, (not related to this bug) there is no need to switch off AC for GLX bug workaround. It just enough to force creation of non-GL evas engine. For example, Minibrowser has --engine parameter and you could try this without recompiling.