From 13d75acaf766631d4fd6baae61c14965f83ab6a7 Mon Sep 17 00:00:00 2001 From: Carl Worth Date: Wed, 10 Jun 2009 16:27:18 -0700 Subject: [PATCH] Add new post on driver stability Mostly a plea to users to run the latest driver and report regressions. --- src/intel/driver_stability.mdwn | 83 +++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 src/intel/driver_stability.mdwn diff --git a/src/intel/driver_stability.mdwn b/src/intel/driver_stability.mdwn new file mode 100644 index 0000000..70da02f --- /dev/null +++ b/src/intel/driver_stability.mdwn @@ -0,0 +1,83 @@ +[[!meta title="On Intel Driver Stability"]] + +[[!tag intel]] + +It's hard for me to believe that my last technical post on the +progress of the Intel graphics driver was nearly a year +ago. Certainly, a lot has happened in that year, and recent +developments have been covered well by +[Keith](http://keithp.com/blogs/Sharpening_the_Intel_Driver_Focus/), +[Eric](http://anholt.livejournal.com/41132.html), and +[Jesse](http://virtuousgeek.org/blog/index.php/jbarnes/2009/05/07/pageflipping_blocking_etc). So +I won't go into any of those details, but I do want to give my +impression of where things stand. + +As my colleagues have described so well, a major restructuring of the +driver is now complete, (KMS, GEM, dri2, removal of XAA, EXA, dri1, +etc.). This restructuring caused months of upheaval, followed by +months of stabilization during which many bugs were shaken out. The +end result is that the primary developers are all optimistic about the +current state of the driver. Things seem better than ever. + +In the meantime, however, it's also obvious that some users are not +happy with the driver, and some have gotten the impression that the +quality is getting consistently worse with time. Some have theorized +that no quality-assurance testing is happening, or that the developers +just plain don't care about regressions. Neither of those theories or +true, so why is there such a disconnect between the developers and the +users? + +One reason for unhappy users is the lag between development happening +and users getting their hands on the code. So the phase of upheaval +and instability might be behind the developers, but some users are +just entering into it. This is exacerbated by the fact that the major +restructuring puts several important components of the driver into the +kernel. It used to be that getting the latest Intel driver just meant +updating an xf86-video-intel module or upgrading an +xserver-xorg-video-intel package. But now it's essential to get a +recent kernel as well, (note that almost all of the major fixes that +Eric describes happened in the kernel, not the user-level driver). And +these fixes aren't in a major kernel release until 2.6.30 which +appeared only today. + +In addition, distributions and users have a tendency to update the +kernel less frequently than user-level components. So when a user +checks out the latest xf86-video-intel from git, (without a kernel +upgrade), not only is that user not getting the "latest driver" as +recommended by the developers, but they might also be running a +combination that the developers and QA never saw nor tested. + +For example, I recently attempted to run the latest-from-git Intel +driver with a kernel version as installed by current Debian +installation CDs. This kernel is ancient with respect to our driver +development (2.6.25 I think). What I found was that the X server would +not start at all. Obviously, we had neglected to test this particular +combination, (so yes, QA isn't perfect---but it also can't cover the +infinite number of possible combinations). Fortunately, the fix was +simple, and appears in the 2.7.99.901 snapshot I just released +(today!) so will appear in the 2.8.0 release very soon. + +The packagers of X for Ubuntu have been working hard to address this +exact problem of the lag between developers and users. They've setup a +repository of packages named +[xorg-edgers](https://launchpad.net/~xorg-edgers) where users can +easily get packages built directly from git. I don't think it includes +the kernel yet, as it will soon hopefully, but this is definitely a +step in the right direction. + +But what about the users that _did_ upgrade their kernel and driver +and are _still_ seeing some major problems? In this case, we really +want to hear from you. We take pride in our work and are committed to +doing our best to make quality releases without regressions. When you +hit some awful behavior, (GPU hang, scrambled mode, abysmal +performance), it may be that you're just hitting a combination of +components or application behavior that we've never seen before. We +want those details and we want to fix the problem. File good [bug +reports](http://intellinuxgraphics.org/how_to_report_bug.html) and +please make use of the "regression" keyword as appropriate. We pay +attention to that. + +Performance regressions are an especially important issue. In fact, +performance is so important that I'll make a separate post about +that. I've got some exciting news to share about performance +measurement. -- 2.43.0