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diff --git a/html/notes/android_swrast.html b/html/notes/android_swrast.html new file mode 100644 index 0000000..0f688ef --- /dev/null +++ b/html/notes/android_swrast.html @@ -0,0 +1,205 @@ +<!doctype html> + +<html class="html-note-page" lang="en"> +<head> + <meta charset="utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1"> + + <title>Software Rendering and Android</title> + <meta name="dcterms.date" content="2024-06-27" /> + + <link rel="stylesheet" href="/assets/style.css"> + <link rel="icon" type="image/x-icon" href="/assets/favicon.svg"> + <link rel="alternate" type="application/atom+xml" title="Fryzek Concepts" href="/feed.xml"> +</head> + +<body> + <div class="header-bar"> + <a href="/index.html"> + <img src="/assets/favicon.svg" alt="frycon logo"> + </a> + <div class="header-links"> + <a href="/now.html" class="header-link">Now</a> + <a href="/about.html" class="header-link">About</a> + <a rel="me" href="https://mastodon.social/@hazematman">Social</a> + </div> + </div> + <main> +<div class="page-title-header-container"> + <h1 class="page-title-header">Software Rendering and Android</h1> + <div class="page-info-container"> + <div class="plant-status"> + <img src="/assets/evergreen.svg"> + <div class="plant-status-text"> + <p>evergreen</p> + </div> + </div> + <div class="page-info-date-container"> + <p class="page-info-date">Published: 2024-06-27</p> + <p class="page-info-date">Last Edited: 2024-06-27</p> + </div> + </div> + </div> +<div class="note-divider"></div> +<div class="main-container"> + <div class="note-body"> +<p>My current project at Igalia has had me working on Mesa’s software +renderers, llvmpipe and lavapipe. I’ve been working to get them running +on Android, and I wanted to document the progress I’ve made, the +challenges I’ve faced, and talk a little bit about the development +process for a project like this. My work is not totally merged into +upstream mesa yet, but you can see the MRs I made here:</p> +<ul> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29344">MR +!29344</a></li> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29785">MR +!29785</a></li> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27805">MR +!27805</a></li> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28735">MR +!28735</a></li> +</ul> +<h2 id="setting-up-an-android-development-environment">Setting up an +Android development environment</h2> +<p>Getting system level software to build and run on Android is +unfortunately not straightforward. Since we are doing software rendering +we don’t need a physical device and instead we can make use of the +Android emulator, and if you didn’t know Android has two emulators, the +common one most people use is “goldfish” and the other lesser known is +“cuttlefish”. For this project I did my work on the cuttlefish emulator +as its meant for testing the Android OS itself instead of just Android +apps and is more reflective of real hardware. The cuttlefish emulator +takes a little bit more work to setup, and I’ve found that it only works +properly in Debian based linux distros. I run Fedora, so I had to run +the emulator in a debian VM.</p> +<p>Thankfully Google has good instructions for building and running +cuttlefish, which you can find <a +href="https://source.android.com/docs/devices/cuttlefish/get-started">here</a>. +The instructions show you how to setup the emulator using nightly build +images from Google. We’ll also need to setup our own Android OS images +so after we’ve confirmed we can run the emulator, we need to start +looking at building AOSP.</p> +<p>For building our own AOSP image, we can also follow the instructions +from Google <a +href="https://source.android.com/docs/setup/build/building">here</a>. +For the target we’ll want +<code>aosp_cf_x86_64_phone-trunk_staging-eng</code>. At this point it’s +a good idea to verify that you can build the image, which you can do by +following the rest of the instructions on the page. Building AOSP from +source does take a while though, so prepare to wait potentially an +entire day for the image to build. Also if you get errors complaining +that you’re out of memory, you can try to reduce the number of parallel +builds. Google officially recommends to have 64GB of RAM, and I only had +32GB so some packages had to be built with the parallel builds set to 1 +so I wouldn’t run out of RAM.</p> +<p>For running this custom-built image on Cuttlefish, you can just copy +all the <code>*.img</code> files from +<code>out/target/product/vsoc_x86_64/</code> to the root cuttlefish +directory, and then launch cuttlefish. If everything worked successfully +you should be able to see your custom built AOSP image running in the +cuttlefish webui.</p> +<h2 id="building-mesa-targeting-android">Building Mesa targeting +Android</h2> +<p>Working from the changes in MR <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29344">!29344</a> +building llvmpipe or lavapipe targeting Android should just work™️. To +get to that stage required a few changes. First llvmpipe actually +already had some support on Android, as long as it was running on a +device that supports a DRM display driver. In that case it could use the +<code>dri</code> window system integration which already works on +Android. I wanted to get llvmpipe (and lavapipe) running without dri, so +I had to add support for Android in the <code>drisw</code> window system +integration.</p> +<p>To support Android in <code>drisw</code>, this mainly meant adding +support for importing dmabuf as framebuffers. The Android windowing +system will provide us with a “gralloc” buffer which inside has a dmabuf +fd that represents the framebuffer. Adding support for importing dmabufs +in drisw means we can import and begin drawing to these frame buffers. +Most the changes to support that can be found in <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/src/gallium/frontends/dri/drisw.c#L405"><code>drisw_allocate_textures</code></a> +and the underlying changes to llvmpipe to support importing dmabufs in +MR <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27805">!27805</a>. +The EGL Android platform code also needed some changes to use the +<code>drisw</code> window system code. Previously this code would only +work with true dri drivers, but with some small tweaks it was possible +to get to have it initialize the drisw window system and then using it +for rendering if no hardware devices are available.</p> +<p>For lavapipe the changes were a lot simpler. The Android Vulkan +loader requires your driver to have <code>HAL_MODULE_INFO_SYM</code> +symbol in the binary, so that got created and populated correctly, +following other Vulkan drivers in Mesa like turnip. Then the image +creation code had to be modified to support the +<code>VK_ANDROID_native_buffer</code> extension which allows the Android +Vulkan loader to create images using Android native buffer handles. +Under the hood this means getting the dmabuf fd from the native buffer +handle. Thankfully mesa already has some common code to handle this, so +I could just use that. Some other small changes were also necessary to +address crashes and other failures that came up during testing.</p> +<p>With the changes out of of the way we can now start building Mesa on +Android. For this project I had to update the Android documentation for +Mesa to include steps for building LLVM for Android since the version +Google ships with the NDK is missing libraries that llvmpipe/lavapipe +need to function. You can see the updated documentation <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/drivers/llvmpipe.rst">here</a> +and <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/android.rst">here</a>. +After sorting out LLVM, building llvmpipe/lavapipe is the same as +building any other Mesa driver for Android: we setup a cross file to +tell meson how to cross compile and then we run meson. At this point you +could manual modify the Android image and copy these files to the vm, +but I also wanted to support building a new AOSP image directly +including the driver. In order to do that you also have to rename the +driver binaries to match Android’s naming convention, and make sure +SO_NAME matches as well. If you check out <a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/android.rst?plain=1#L183">this</a> +section of the documentation I wrote, it covers how to do that.</p> +<p>If you followed all of that you should have built an version of +llvmpipe and lavapipe that you can run on Android’s cuttlefish +emulator.</p> +<figure> +<img src="/assets/2024-06-27-android-swrast/lavapipe.png" +alt="Android running lavapipe" /> +<figcaption aria-hidden="true">Android running lavapipe</figcaption> +</figure> +<h2 id="references">References</h2> +<ul> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29344" +class="uri">https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29344</a> +<ul> +<li>Main MR with Android changes</li> +</ul></li> +<li><a +href="https://source.android.com/docs/devices/cuttlefish/get-started" +class="uri">https://source.android.com/docs/devices/cuttlefish/get-started</a> +<ul> +<li>Google’s official guide for getting started with the Cuttlefish +emulator</li> +</ul></li> +<li><a href="https://source.android.com/docs/setup/build/building" +class="uri">https://source.android.com/docs/setup/build/building</a> +<ul> +<li>Google’s official guide for building AOSP images</li> +</ul></li> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/drivers/llvmpipe.rst" +class="uri">https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/drivers/llvmpipe.rst</a> +<ul> +<li>My updated documentation in MR for llvmpipe</li> +</ul></li> +<li><a +href="https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/android.rst" +class="uri">https://gitlab.freedesktop.org/mesa/mesa/-/blob/9705df53408777d493eab19e5a58c432c1e75acb/docs/android.rst</a> +<ul> +<li>My updated documentation in MR for Android integration in mesa</li> +</ul></li> +</ul> + </div> +</div> </main> +</body> +</html> |