Re: [RFC 0/1] DRM Node Probing functionality
Hi Rob, On Thu, Apr 12, 2018 at 12:56 PM Robert Foss wrote: > *Resend the whole actual series* > This patch implements a simple function for matching DRM device FDs against > the desired properties of a device that you are looking for. > The properties that are possible to look for are the elements of DrmVersion > and DrmDevice. > The discussion that led to this series can be found here: > https://lists.freedesktop.org/archives/mesa-dev/2018-January/183878.html > In the previous discussion we left off having settled on implementing this > in mesa/src/loader/loader.c, which I initially did. But the code ended up being > so generic that there's no reason for it not to live in libdrm, since it can be > used for any compositor and mesa. > The implementer will still have to iterate through all of the devices available > on the target, and see if they match. This additional functionality could be > moved into libdrm at a later point if it turns out that all of the users do this > in the same manner. > If there is some variety, for example with selecting fallback devices if nothing > matches maybe it is best left up to the user of libdrm. > The biggest problem with the approach as implemented, the way I see it, is how > we match against the DrmVersion/DrmDevice of a given FD. > Currently we use DrmVersion & DrmDevice as supplied by the caller to define what > we are looking for. > This is a little bit problematic, especially for DrmDevice, since all of the > elements of the struct do not have enough bitspace to signal that we are > uninterested in looking for that specific element. DrmDevice uses > drmDevicesEqual() to do what amounts to a memcmp of the DrmDevice argument and > the one of the FD. So looking for any device on any PCI bus with just the > PCI vendor ID supplied isn't possible. > An alternative Daniel Stone suggested is adding enums for different properties > and allowing the caller to supply a list of properties that are interesting and > their values. In terms of long-term maintainership this might be less pleasant > than the approach of the current implementation. I'm personally okay with how patch 1 implements the matching. Thanks for this work. Looking forward to the Mesa probing helper, which uses this! :) P.S. I normally use my @chromium.org email for mailing lists. Best regards, Tomasz ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
[RFC 0/1] DRM Node Probing functionality
*Resend the whole actual series* This patch implements a simple function for matching DRM device FDs against the desired properties of a device that you are looking for. The properties that are possible to look for are the elements of DrmVersion and DrmDevice. The discussion that led to this series can be found here: https://lists.freedesktop.org/archives/mesa-dev/2018-January/183878.html In the previous discussion we left off having settled on implementing this in mesa/src/loader/loader.c, which I initially did. But the code ended up being so generic that there's no reason for it not to live in libdrm, since it can be used for any compositor and mesa. The implementer will still have to iterate through all of the devices available on the target, and see if they match. This additional functionality could be moved into libdrm at a later point if it turns out that all of the users do this in the same manner. If there is some variety, for example with selecting fallback devices if nothing matches maybe it is best left up to the user of libdrm. The biggest problem with the approach as implemented, the way I see it, is how we match against the DrmVersion/DrmDevice of a given FD. Currently we use DrmVersion & DrmDevice as supplied by the caller to define what we are looking for. This is a little bit problematic, especially for DrmDevice, since all of the elements of the struct do not have enough bitspace to signal that we are uninterested in looking for that specific element. DrmDevice uses drmDevicesEqual() to do what amounts to a memcmp of the DrmDevice argument and the one of the FD. So looking for any device on any PCI bus with just the PCI vendor ID supplied isn't possible. An alternative Daniel Stone suggested is adding enums for different properties and allowing the caller to supply a list of properties that are interesting and their values. In terms of long-term maintainership this might be less pleasant than the approach of the current implementation. Robert Foss (1): xf86drm: Add drmHandleMatch func xf86drm.h | 2 ++ xf86drmMode.c | 69 +++ 2 files changed, 71 insertions(+) -- 2.14.1 ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
[RFC 0/1] DRM Node Probing functionality
This patch implements a simple function for matching DRM device FDs against the desired properties of a device that you are looking for. The properties that are possible to look for are the elements of DrmVersion and DrmDevice. The discussion that led to this series can be found here: https://lists.freedesktop.org/archives/mesa-dev/2018-January/183878.html In the previous discussion we left off having settled on implementing this in mesa/src/loader/loader.c, which I initially did. But the code ended up being so generic that there's no reason for it not to live in libdrm, since it can be used for any compositor and mesa. The implementer will still have to iterate through all of the devices available on the target, and see if they match. This additional functionality could be moved into libdrm at a later point if it turns out that all of the users do this in the same manner. If there is some variety, for example with selecting fallback devices if nothing matches maybe it is best left up to the user of libdrm. The biggest problem with the approach as implemented, the way I see it, is how we match against the DrmVersion/DrmDevice of a given FD. Currently we use DrmVersion & DrmDevice as supplied by the caller to define what we are looking for. This is a little bit problematic, especially for DrmDevice, since all of the elements of the struct do not have enough bitspace to signal that we are uninterested in looking for that specific element. DrmDevice uses drmDevicesEqual() to do what amounts to a memcmp of the DrmDevice argument and the one of the FD. So looking for any device on any PCI bus with just the PCI vendor ID supplied isn't possible. An alternative Daniel Stone suggested is adding enums for different properties and allowing the caller to supply a list of properties that are interesting and their values. In terms of long-term maintainership this might be less pleasant than the approach of the current implementation. Robert Foss (1): xf86drm: Add drmHandleMatch func xf86drm.h | 2 ++ xf86drmMode.c | 69 +++ 2 files changed, 71 insertions(+) -- 2.14.1 ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel