On Monday 21 January 2008 14:37, Matthew Garrett wrote: > On Mon, Jan 21, 2008 at 02:00:41PM -0500, Theodore Tso wrote: > > > Well, unless until Video card vendors give us their secret interfaves > > to reinitialize their cards, we're never going to figure it out, > > right? > > There's (not yet mainline) code to do this on Intel, and it looks like > AtomBios based ATIs (some r400s, all r500s and later) should be trivial. > The work the Nouveau people have been doing is also very promising, and > I suspect we can do cold boot there before too long. I was going to do > some work on this this week, but my ATI machine got stolen... > > > At least for vendors like Lenovo, where some laptops will be > > shipping with Intel cards where we will eventually be able do our own > > video reinit after suspend, and some with Nvidia chipsets where it > > doesn't seem terribly likely until someone at Nvidia has a change of > > heart, the BIOS won't be able to use the "please reinit video" as a > > general "Linux" indicator, since they will need to support laptops > > with Good as well as Evil graphics chipsets. :-) > > The problem is that we don't inherently know if we can support > reinitialising video natively until the video driver is loaded, and > there's a high probability that that's going to come from a module. > We're already executing ACPI by then, so the firmware's had the > opportunity to stash an incorrect value and can blow everything up later > on. Right, if we go down this path, we'd have to do it as a boot parameter in order to enable/disable the hook before any platform AML gets a chance to see it. note that acpi_osi=string and acpi_osi=!string are available starting in 2.6.23. You get to add up to 1 string, and you get to remove as many pre-existing strings as you like. of course, this trick would require the distro installer to know tha a native-video driver were present, and modify the bootparms accordingly. > If vendors want their laptops to work on Linux, then the best thing > they can do is help us get our drivers working properly. True. For Intel graphics, Intel/OTC is working on getting this fixed. It has not been a quick fix -- the pipeline is long... Maybe the quick fix is to enhance the workarounds in s2ram and simply deal with it that way until native video drivers are available? > Now, stuff like a standardised entrypoint into ACPI that reinitialises > the video - that would be helpful, since we could choose whether to call > it or not which means whether or not something gets screwed up is > determined by us and not the vendor. Even if we (Linux) proposed this and it got added to the spec, it wouldn't have any real effect b/c windows doesn't need it, so most machines wouldn't implement it. Smarter native video drivers is clearly the preferred path. -Len - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
