From: Eleni Maria Stea <estea@igalia.com>
Date: Wed, 19 May 2021 20:07:09 +0000 (+0300)
Subject: quick backup, in the middle of dma
X-Git-Url: https://eleni.mutantstargoat.com/git/?p=webkit_codecamp;a=commitdiff_plain;h=cada10a2233744023a73f82e8a81553b4c4bf0db

quick backup, in the middle of dma
---

diff --git a/codecamp.tex b/codecamp.tex
index 6c41365..4a9cb6e 100644
--- a/codecamp.tex
+++ b/codecamp.tex
@@ -728,11 +728,105 @@ program}
     \frametitle{DMA buffers for the win!}
 
     \begin{center}
+		\textbf{\color{coolblack}Fortunately we are on Linux!}
+
+		\setbeamercolor{block body}{bg=white}
+		\setbeamercolor{block title}{bg=white, fg=coolblack}
+		\begin{block}{\scriptsize{There is a Linux kernel framework that can be used for
+			content sharing between different Linux drivers!}}
+
+			\vspace{-0.1cm}
+			\begin{table}[t]
+				\centering
+				\begin{tabular}{l}
+					\begin{adjustbox}{max width=\textwidth}
+						\adjustbox{valign=t}{\includegraphics[height=3.1cm]{data/dma_buf_sharing.png}}
+					\end{adjustbox}
+				\end{tabular}
+			\end{table}
+
+			\textbf{\scriptsize{\color{coolblack}A few things that need our attention:}}\\
+			\vspace{0.1cm}
+
+			\setbeamertemplate{itemize/enumerate body begin}{\tiny}
+			\begin{itemize}
+				\item There are {\color{coolblack}EGL and OpenGL/GLESv2
+					extensions} to make this content sharing easier!
+				\item It's {\color{coolblack}driver independent}!
+				\item It works with {\color{coolblack}multiple processes}!
+				\item As long as ANGLE can expose the required extensions to
+					import a dma\_buf file descriptor this method is
+					{\color{coolblack}"ANGLE backend
+					independent"}!
+				\item Works {\color{coolblack}only on Linux}... but in case of
+					WPE we won't need to support other systems! (Žan Doberšek)
+			\end{itemize}
+		\end{block}
     \end{center}
 \end{frame}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+\begin{frame}
+	\frametitle{Extensions and new approach}
+
+	\setbeamercolor{block body}{bg=white}
+	\setbeamertemplate{itemize/enumerate body begin}{\tiny}
+
+	\begin{block}{How the kernel DMA buffers would help us avoid copying
+		the WebGL texture data?}
+
+		\begin{center}
+			\begin{itemize}
+				\item Each texture is backed by a Linux kernel dma\_buffer.
+				\item Multiple textures can use the same dma buffer as backing
+					storage if they meet some requirements.
+				\item We can export the file descriptor of one buffer from one
+					driver and use it to access the buffer from the other
+					driver.
+				\item So we can export the FD that corresponds to the compositor
+					texture, import it in WebGL when we create the render target
+					and when the WebGL texture is filled, the compositor texture
+					will be also filled, as they share the backing storage!
+			\end{itemize}
+		\end{center}
+	\end{block}
+	\begin{block}{Some EGL extensions make easy this exchange:}
+		\begin{center}
+			\begin{itemize}
+				\item
+					\href{https://www.khronos.org/registry/EGL/extensions/MESA/EGL\_MESA\_image\_dma\_buf\_export.txt}{EGL\_MESA\_image\_dma\_buf\_export}:
+					This extension allows creating one or multiple Linux dma\_buf
+					file descriptors from the EGLImage that corresponds to a texture.
+				\item \href{https://www.khronos.org/registry/EGL/extensions/EXT/EGL\_EXT\_image\_dma\_buf\_import.txt}{EGL\_EXT\_image\_dma\_buf\_import}:
+					This extension allows creating an EGLImage (that will be used to create a
+					texture) from one or multiple Linux dma\_buf file
+					descriptors.
+				\item {}{}
+				\item {}{}
+			\end{itemize}
+		\end{center}
+	\end{block}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\begin{frame}
+	\frametitle{Example use}
+
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\begin{frame}
+	\frametitle{Example program}
+
+	Code:
+	Blog post:
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%