If nothing else depends on the weird second open behavior it should be safe to change it.
Dave? Jesse On Wed, 14 Oct 2009 19:39:44 +0200 "Defnet, Benjamin R" <[email protected]> wrote: > Does anyone have any feedback for me? I'm able to modify libdrm to > make things work for me, but I'm pretty sure that isn't the right > thing to do. > > ________________________________ > From: Defnet, Benjamin R > Sent: Monday, October 12, 2009 8:59 PM > To: '[email protected]' > Subject: drmOpenByName opening incorrect minor? > > Here is my situation. I have two drm devices "alpha" and "beta" both > mapped to the same hw with the same PCI Bus ID. "alpha" is at minor > 0 and "beta" is at minor 1. > > If I do the following: > > drmOpen("beta", NULL); > drmOpen("beta", NULL); > > The second call will actually return a file descriptor pointing to > the "alpha" device. Based on my code traces, this is because for the > second call, drmOpenByName( ) will iterate through the minors and > find "beta" at minor 1, but the PCI Bus ID will be non-null due to > the previous drmOpen, so it will skip that and not find any other > name matches. It will then try the "Backward-compatiblity /proc > support" loop. It will find a match at minor 1, but will then call > drmOpenByBusid( ). drmOpenByBusid( ) will again iterate through the > minors looking for a PCI Bus ID match and will find one at minor 0, > the "alpha" drm device, so it will open that and return the fd. > > This obviously isn't what I expected. I expected it to open minor 1, > the "beta" drm device. I end up using the wrong fd and get crashes > because my "alpha" device obviously can't handle the "beta" ioctls. > > A few questions: > > 1) Is this expected behavior? > 2) In drmOpenByName( ), why does it reject a match if the PCI > Bus ID is non-null? drmOpenByBusID( ) doesn't do that. 3) Any > ideas how I can make this work assuming my setup above (2 drm devices > with same PCI Bus ID) can't change? > > Thank you, > > Ben -- Jesse Barnes, Intel Open Source Technology Center ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference -- _______________________________________________ Dri-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dri-devel
