Interview with Feral Interactive about their ports and Mesa drivers, Steam keys offered for Mesa developers

It has been a while since we officially spoke to Feral Interactive [Official Site] about their Linux ports, with the last time being in June 2014. It’s time to get reacquainted and see where things stand right now.

While we ask an assortment of questions, the main bulk of the interview is aimed at discussions around Mesa. Mesa is a hot topic for a lot of people, especially those on AMD hardware, so we hope you will find this interesting.

As usual, we will start with a brief introduction. Then we will split off into questions from both myself and GOL contributor BTRE who teamed up with me for this interview.

Without any further rambling, here's the interview!

GOL Liam: Many in the community probably know you already, but for those who don’t please tell us a little bit about yourself and Feral Interactive's history with Linux.

Feral Edwin: Feral started bringing games to the Mac in 1996, and in 2014 we started bringing games to Linux as well. Since then we’ve published 22 (!) games for Linux including standalone expansions.

My name is Edwin and I’m the Head of Production at Feral; you might have also seen me on forums as “EddDeDuck”. I’ve worked on just over 100 games now, including all of our Linux titles. I spend my time between my Linux and Mac machines and usually have both within arm’s reach.

Feral Marc: Hi, I’m the Linux Group Lead at Feral. I’ve worked in some way on every single Linux title Feral has shipped and generally split my time between programming and helping organise our penguins.

GOL Liam: Do you use Linux at home personally? If so, what's your favourite distribution and why?

Feral Edwin: I’ve got a few Linux setups at home. My main Linux desktop is running Ubuntu 16.10 right now, although I have Ubuntu 16.04 (LTS) on my server(s). I am interested in giving Antergos a try; I just need to find the time in between all these games!

Feral Marc: I currently run Antergos on my desktop, with a boot of Fedora 25 for wayland testing. I also have a couple of Pis running Raspbian and my laptop is on Mint 18. Antergos is my favourite at the moment, it's great to finally have an Arch flavour I can recommend to friends.”

GOL Liam: I see my Antergos article has swayed a few more people then...



GOL Liam: In our last interview back in 2014, you stated that Feral Interactive started porting games to Linux due to SteamOS and Steam Machines. Since they are now out in the wild, how do you feel about them and about continuing to support Linux with ports?

Feral Edwin/Marc: SteamOS and Valve’s support brought a lot of exposure to Linux as a platform, which helped get the ball rolling for this latest surge of gaming on Linux. SteamOS has the advantage of being a more tightly controlled version of Linux similar to LTS (Long Term Support) versions of popular distros but targeted specifically at gaming. This gives new developers a stable target to aim at when bringing titles to the platform.

Instead of making predictions about the future, we’d like to spin the discussion 180 degrees and talk about what the last two years have brought us.

In 2014, when Feral shipped XCOM: Enemy Unknown for Linux, there were perhaps two other modern AAA games released on Linux around the same time. Mesa had just shipped 10.2 with OpenGL 3.3 support for Intel and AMD on some cards. OpenGL 4.5 was not yet available.

Since then, Feral has shipped over 20 more AAA games, Mesa now has OpenGL 4.5 support since 13.0.1, and Vulkan has gone from not even existing as a concept to being fully released.

The exciting thing about game dev is that the industry is always moving; we may make a big, fast game this week, but there will be an even bigger, faster game the next. There are always new standards to aim for, but we’ve come a long way as a platform. Let’s see if the next two years are as exciting!



GOL Liam: How has Feral’s own testing process evolved from your first Linux port of XCOM: Enemy Unknown, to your latest port?

Feral Edwin/Marc: We see testing as part of a large feedback loop in which all the experience and information we get from one game feeds into the next. With XCOM: Enemy Unknown we were starting out on Linux, and so deliberately aimed to make sure the core game experience was right and not to have too many extra features.

Since we ported XCOM: Enemy Unknown here are a few things we have added to our games and test for:

• Robust launch scripts - We've improved our launch scripts incrementally with every game, to deal with edge cases and other support requests. Although we only officially support Ubuntu and SteamOS, we have tweaked the launch scripts to make our games work around the more well-known issues on other distros. If you are on an unsupported distro I recommend you look at the launch script; it’s fully commented and might help you solve some issues. If you do solve an issue, please let us know! We’re keen to keep improving it.


• Feral Launcher - We’ve had a launcher on Mac for a long time, but it took a little while to come to Linux as we worked out the best way of doing it. This was a major improvement for Linux users, because in one move we added:
• Monitor Selector so you can choose what monitor to play on.
• Workshop Mod panel when the game supports mods.
• Support tab that allows generation of a support file that helps us fix user issues quicker.
• Documentation panel, which allows quick access to the Manual, Read Me and FAQ.
• Pre-game warnings if you have incorrect drivers or other unsupported issues. This has helped reduce support issues as people know to upgrade their system to avoid an issue instead of just crashing or having graphical issues.
• Shiny custom artwork.



• Support on different hardware - We’ve added more hardware as new graphics cards have been released. When we started with XCOM: Enemy Unknown we had a small selection of the currently manufactured cards but now we have an extra two years worth of graphics cards in the office so we can test on most variants from all three GPU vendors. We’ve also added new machines to run these cards using CPUs from both Intel and AMD.


• Mesa - We’ve used Mesa since XCOM: Enemy Unknown. In fact, our first patch submitted to Mesa was for a render issue on Intel GPUs during development of the game. Since then we’ve logged bugs with reproduction steps, provided Mesa developers with game keys, and in some cases submitted patches to fix driver bugs.


• External Testing - Over the past few years, people in the Linux community have sent us feedback about the games we have published, and we have used that to try and improve what we do. In some cases we have signed them up to our external test group. This has got us useful feedback from end users allowing us to fix issues with unsupported distros so our games launch on some of the less common setups without workarounds. It also allows us to test strange keyboard layouts and hardware that we might not have direct access to.

GOL BTRE: A little over a year ago Mesa only supported OpenGL up to version 4.1 and now it includes full support for OpenGL 4.5. Even Vulkan drivers have made their way into Mesa for both Intel and newer AMD GPUs. How do you feel about Mesa’s evolution and how does it currently measure up to proprietary drivers?  

Feral Edwin: Mesa has come a long way in the last six months and we’re very pleased with that. On AMD in particular we now see Mesa as a strong competitor to the AMDGPU-PRO drivers in terms of features and performance. Our next aim is to make it easier for the community to install the latest official releases instead of latest git.

Feral Marc: From a purely technical standpoint, Mesa now hits our targets for OpenGL features, but there’s still some work to be done in terms of stability and performance. It’s exciting to see that the Vulkan drivers have made it in.



GOL BTRE: When porting a game, how much time do you typically dedicate to testing with Mesa? Which versions and hardware do you test together?

Feral Edwin: These days with full 4.5 support we aim to test the dedicated GPUs evenly, including Intel when it meets the minimum specs. We have a wide range of AMD cards covering the key models from the 200, 300 and 400 series of cards. These are distributed among our QA and dev teams so every title has daily access to AMD hardware. We also have a pile of Intel Iris Pro hardware for testing. Finally we have Nvidia cards all the way from the 600 series up to the latest 10x0 series.

In QA we usually stick to the latest stable release from Mesa.org, but we’ll update to the latest git when needed. This happens quite frequently as we often require the most recent fixes and updates.

Feral Marc: Practically every game has had a developer working on it using Mesa as their daily driver, usually compiled from source or using their distributions equivalent to the oibaf/padoka or xorg-edgers ppas. I personally started compiling Mesa from source on my Intel machine way back when working on XCOM: Enemy Unknown.

GOL BTRE: How much of your porting process is spent on dealing with driver-specific issues? Does Mesa get the same amount of attention as proprietary drivers when it comes to bugfixing and reporting upstream?

Feral Marc: Driver-specific issues with OpenGL are common on all vendors due to the ambiguity of the API in places. The amount of time spent on dealing with driver-specific issues varies very much by game

In regards to fixing driver specific issues, Mesa does tend to get more attention at Feral. This is because as developers we prefer to find out the exact cause of the problem we run into, and having source access gives us the tools to delve deep and fix it. Our recent fix to Mesa’s implementation of GL_PRIMITIVE_RESTART for Deus Ex: Mankind Divided is a good example of this.

GOL Liam: What are you hoping is next for Mesa development to help with Feral ports?

Feral Marc: Primarily finalised work on the on-disk shader cache. Development tools are a focus as well – Nvidia provide an incredibly powerful debugger, the Linux Graphics Debugger, which unfortunately only works on their hardware. We’re working closely with the Mesa developers who are looking to provide similar tools. A final wish is for nouveau to mature in terms of performance.



GOL Liam: From what we know, you actually offer all your games to Mesa developers. How would people reach out to Feral for access if they work on Mesa? Have many taken you up on the offer?

We’ve provided keys to developers working on issues that we’ve logged or affect our games. This started way back with XCOM: Enemy Unknown.

We also hand out keys to some of the most active developers on Mesa. Giving them copies of all of our games makes it easier for them to test any work they are doing against multiple complex examples. This in turn means any implementations and fixes are more likely to be robust and work correctly against all examples.

GOL Liam: You recently asked Canonical and the Ubuntu community to get Mesa updates into a PPA, how has the response been so far? If it doesn’t get sorted, will Feral look to provide their own PPA?

Feral Edwin/Marc: It’s early days, and we’re looking into all the options to make Mesa easier to access for the entire community.

GOL Liam: With the recent strides Mesa has made, do you think Valve will opt for using Mesa over proprietary drivers for specific cards in future for SteamOS?

Feral Edwin/Marc: it would be nice if SteamOS supported the latest Mesa versions alongside the proprietary drivers. GLVND (OpenGL Vendor-Neutral Dispatch) was a step towards making this happen.

GOL Liam: There’s still confusion on what games you actually support with Mesa and what games you don’t. Could you give us a list of what games are and aren’t and mention what’s holding back games that aren’t yet supported?

Feral Edwin/Marc: Here is a link to a table of our titles and levels of support in Mesa. We also have notes on what our basic tests and user feedback have indicated for the unsupported titles, currently all our games render on Mesa/RadeonSI but with various open issues.

Official support requires that QA test all the card ranges across all the different settings. With the latest Mesa (17) and AMDGPU-PRO drivers (16.50) being released, more games render correctly, which means we should be able to officially support more games.

XCOM 2 is a good example. We added official AMD support with Mesa drivers in December 2016.

GOL Liam: With the recent improvements to Mesa, are we looking at more releases in 2017 with day-1 Mesa support?

Feral Edwin/Marc: We have been able to pull this off with our last three releases on Linux – Total War: WARHAMMER, DiRT Rally and HITMAN. We hope to keep this run going for the rest of 2017.

GOL BTRE: Performance on AMD GPUs using Mesa has generally been poorer than Nvidia cards using proprietary drivers. Is there any chance we will see patches with further optimizations in existing ports from Feral? Or will AMD users have to wait for Mesa drivers to mature some more?

Feral Marc: In reality it will be a mixture of both. In some cases the driver improvements will make the game faster without any patching needed, and in others new features and fixes in Mesa mean we can patch the game to run better and faster.

Feral Edwin: It’s also completely possible we have something in our code that Mesa exposes and we should fix, but that’s super rare and should never happen, right Marc? ;)

Feral Marc: No comment...



GOL Liam: The Feral team recently mentioned during a livestream that this year, Feral will be doing a Vulkan port. Will you be looking to update an older game, or will this be with a brand new port?

Feral Edwin: We confirmed we are looking towards a Vulkan implementation in the first half of 2017. Right now we don't have any information to share about which game will be first. I asked Marc a few times and he just shook his Magic 8-Ball and said "Reply hazy, try again".

Feral Marc: *shake* Ask again later

GOL BTRE: What are your thoughts on the current Vulkan drivers on Linux? If it’s not too early to say, for your future Vulkan ports will you be looking into supporting radv for AMD GPUs since it’s now part of Mesa?

Feral Marc: On the tech side, the current status is promising. The Khronos Vulkan Conformance Tests do a lot to ensure drivers behave correctly, though it’s still early days and they haven’t yet been truly stress-tested by a large number of games. We’re aiming to support all the major vendors and drivers, but it’s too early to say we won’t run into any blocking issues.

GOL Liam: 2016 was an absolute knock-out year for Linux ports from Feral Interactive! 2017 has started off really nicely, is the rest of 2017 likely to be just as exciting?

Feral Edwin: We hope so!

Feral Marc: I should get back to work then…

GOL Liam: Be honest, how many of those delicious cupcakes sent by the community did you hoard for yourself? Or is there a different treat that has your heart?

Feral Marc: Edwin ate all of them himself. I’m a tricolore salad kind of person myself so I didn’t mind.

Feral Edwin: You’re not blaming me, Marc! I was having a day off when they arrived. As for who ate them I seem to recall Marc’s face in the photographs. ;) I even have evidence! https://twitter.com/feralgames/status/791601845147959296

Feral Marc: Shh… huge thanks to Michael for sending them, though!

GOL BTRE: Any last thoughts on Mesa, Linux or porting in general you would like to share with us?

Feral Edwin: We’ve mentioned before that we’ve handed out keys to particularly active Mesa developers to help them develop new features, fix bugs, and also to thank them for their hard work making the drivers better for everyone.

We’re keen to extend this to the Mesa community in a more formal manner starting today. So if you’re a Mesa contributor this next bit should (hopefully) be pretty exciting!

If you have 25 commits or more to Mesa (including DRI-type stuff in the kernel) in the past five years, please drop us an email at [email protected]. Put 'Steam' in the subject and tell us your freedesktop username and Steam username.

Once we verify your account details, we will send you a special Steam Key granting you access to every game Feral has released for Linux on Steam. This will automatically be updated to add support for new games as they are released!

You have all made Mesa better for everyone and we hope you enjoying playing our games, which were only made possible through your hard work on the drivers. Additionally, having access to all our games should hopefully make your future work on Mesa easier as you’ll have over 20 applications to use as test cases. :)

Thanks for having us, fellow penguins. We’ll waddle off now.


I would like to thank Edwin and Marc for doing the interview with myself and BTRE.

The work Feral Interactive put into helping Linux become a gaming platform is quite incredible. Thanks to Feral we have some really high quality popular games on Linux and it looks like this is going to continue! I personally consider Feral Interactive to be one of our biggest champions next to Valve for pushing Linux forward so much.

Thanks as well to the Mesa team, for their constant effort in improving Linux GPU drivers. Article taken from GamingOnLinux.com.