| Message ID | 7777ff70e2be0663de4398aa6f75f0c54146cbfc.1709727127.git.jani.nikula@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: better high level abstraction for display | expand |
On Wed, 06 Mar 2024, Jani Nikula <jani.nikula@intel.com> wrote: > Long term goal: Separate display code from struct drm_i915_private and > i915_drv.h, and everything in them. Ditto for xe. > > First step, draft some ideas how we could use struct intel_display as > the main device structure for display, while struct drm_device remains > in struct drm_i915_private (or, in the case of xe, in struct xe_device). > > To get at struct drm_device * given a struct intel_display *, simply > store a backpointer. > > To get at struct intel_display * given a struct drm_device *, require > storing a struct intel_display * right after struct drm_device in > memory. It's slightly hackish, but devm_drm_dev_alloc() facilitates > defining the enclosing struct as we wish. To emphasize, getting from struct drm_device * to struct intel_display * is the biggest problem this solves. We have a lot of drm hooks that have a drm device/connector/encoder/etc parameter and no additional context. We can always get from other objects to the drm device, but how to get from that to intel_display? We don't want to know the definitions of struct drm_i915_private or struct xe_device within display code. We don't want to have a function call to i915 or xe cores to translate drm device to intel_display. > A shared named struct for this would be nice, but that would require > changing all the i915->drm and xe->drm dereferences. The use of an > unnamed __packed struct avoids that. To elaborate, this means struct foo { struct drm_device drm; struct intel_display *__intel_display_private; }; struct drm_i915_private { struct foo bar; /* ... */ }; So display code could use container_of to get from struct drm device to struct foo, and thus __intel_display_private. However, *all* of i915 and xe core code would have to be modified to fix i915->drm references to i915->bar.drm. Not cool. BR, Jani. > > Users are added in follow-up patches; the patches may be squashed > together before final submission. > > Signed-off-by: Jani Nikula <jani.nikula@intel.com> > --- > drivers/gpu/drm/i915/display/intel_display_core.h | 3 +++ > .../gpu/drm/i915/display/intel_display_device.c | 13 +++++++++++++ > drivers/gpu/drm/i915/i915_drv.h | 11 ++++++++++- > drivers/gpu/drm/xe/xe_device_types.h | 15 +++++++++++++-- > 4 files changed, 39 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h > index 2167dbee5eea..85b542bb45e6 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_core.h > +++ b/drivers/gpu/drm/i915/display/intel_display_core.h > @@ -282,6 +282,9 @@ struct intel_wm { > }; > > struct intel_display { > + /* drm device backpointer */ > + struct drm_device *drm; > + > /* Display functions */ > struct { > /* Top level crtc-ish functions */ > diff --git a/drivers/gpu/drm/i915/display/intel_display_device.c b/drivers/gpu/drm/i915/display/intel_display_device.c > index c02d79b50006..63de9917e346 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_device.c > +++ b/drivers/gpu/drm/i915/display/intel_display_device.c > @@ -922,6 +922,19 @@ void intel_display_device_probe(struct drm_i915_private *i915) > const struct intel_display_device_info *info; > u16 ver, rel, step; > > + /* > + * These are here for now to do them as early as possible. i915 has just > + * been allocated, drm isn't even initialized yet, but we have the > + * pointer. > + * > + * Later on, the display probe would allocate struct intel_display > + * itself, and return the pointer to the caller, for whom struct > + * intel_display would be an opaque type, a cookie to be passed on to > + * display functions. > + */ > + i915->__intel_display_private = &i915->display; > + i915->display.drm = &i915->drm; > + > if (HAS_GMD_ID(i915)) > info = probe_gmdid_display(i915, &ver, &rel, &step); > else > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index e81b3b2858ac..2e80afbe7a4e 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -185,7 +185,16 @@ struct i915_selftest_stash { > }; > > struct drm_i915_private { > - struct drm_device drm; > + struct { > + struct drm_device drm; > + > + /* > + * Display private data. Do *not* access directly. Must be > + * placed right after drm_device to facilitate getting to it > + * given a drm device pointer. > + */ > + struct intel_display *__intel_display_private; > + } __packed; > > struct intel_display display; > > diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h > index 9785eef2e5a4..0347fbc925c9 100644 > --- a/drivers/gpu/drm/xe/xe_device_types.h > +++ b/drivers/gpu/drm/xe/xe_device_types.h > @@ -210,8 +210,19 @@ struct xe_tile { > * struct xe_device - Top level struct of XE device > */ > struct xe_device { > - /** @drm: drm device */ > - struct drm_device drm; > + struct { > + /** @drm: drm device */ > + struct drm_device drm; > + > +#if IS_ENABLED(CONFIG_DRM_XE_DISPLAY) > + /** > + * @__intel_display_private: Display private data. Do *not* > + * access directly. Must be placed right after drm_device to > + * facilitate getting to it given a drm device pointer. > + */ > + struct intel_display *__intel_display_private; > +#endif > + } __packed; > > /** @devcoredump: device coredump */ > struct xe_devcoredump devcoredump;
diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h index 2167dbee5eea..85b542bb45e6 100644 --- a/drivers/gpu/drm/i915/display/intel_display_core.h +++ b/drivers/gpu/drm/i915/display/intel_display_core.h @@ -282,6 +282,9 @@ struct intel_wm { }; struct intel_display { + /* drm device backpointer */ + struct drm_device *drm; + /* Display functions */ struct { /* Top level crtc-ish functions */ diff --git a/drivers/gpu/drm/i915/display/intel_display_device.c b/drivers/gpu/drm/i915/display/intel_display_device.c index c02d79b50006..63de9917e346 100644 --- a/drivers/gpu/drm/i915/display/intel_display_device.c +++ b/drivers/gpu/drm/i915/display/intel_display_device.c @@ -922,6 +922,19 @@ void intel_display_device_probe(struct drm_i915_private *i915) const struct intel_display_device_info *info; u16 ver, rel, step; + /* + * These are here for now to do them as early as possible. i915 has just + * been allocated, drm isn't even initialized yet, but we have the + * pointer. + * + * Later on, the display probe would allocate struct intel_display + * itself, and return the pointer to the caller, for whom struct + * intel_display would be an opaque type, a cookie to be passed on to + * display functions. + */ + i915->__intel_display_private = &i915->display; + i915->display.drm = &i915->drm; + if (HAS_GMD_ID(i915)) info = probe_gmdid_display(i915, &ver, &rel, &step); else diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index e81b3b2858ac..2e80afbe7a4e 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -185,7 +185,16 @@ struct i915_selftest_stash { }; struct drm_i915_private { - struct drm_device drm; + struct { + struct drm_device drm; + + /* + * Display private data. Do *not* access directly. Must be + * placed right after drm_device to facilitate getting to it + * given a drm device pointer. + */ + struct intel_display *__intel_display_private; + } __packed; struct intel_display display; diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h index 9785eef2e5a4..0347fbc925c9 100644 --- a/drivers/gpu/drm/xe/xe_device_types.h +++ b/drivers/gpu/drm/xe/xe_device_types.h @@ -210,8 +210,19 @@ struct xe_tile { * struct xe_device - Top level struct of XE device */ struct xe_device { - /** @drm: drm device */ - struct drm_device drm; + struct { + /** @drm: drm device */ + struct drm_device drm; + +#if IS_ENABLED(CONFIG_DRM_XE_DISPLAY) + /** + * @__intel_display_private: Display private data. Do *not* + * access directly. Must be placed right after drm_device to + * facilitate getting to it given a drm device pointer. + */ + struct intel_display *__intel_display_private; +#endif + } __packed; /** @devcoredump: device coredump */ struct xe_devcoredump devcoredump;
Long term goal: Separate display code from struct drm_i915_private and i915_drv.h, and everything in them. Ditto for xe. First step, draft some ideas how we could use struct intel_display as the main device structure for display, while struct drm_device remains in struct drm_i915_private (or, in the case of xe, in struct xe_device). To get at struct drm_device * given a struct intel_display *, simply store a backpointer. To get at struct intel_display * given a struct drm_device *, require storing a struct intel_display * right after struct drm_device in memory. It's slightly hackish, but devm_drm_dev_alloc() facilitates defining the enclosing struct as we wish. A shared named struct for this would be nice, but that would require changing all the i915->drm and xe->drm dereferences. The use of an unnamed __packed struct avoids that. Users are added in follow-up patches; the patches may be squashed together before final submission. Signed-off-by: Jani Nikula <jani.nikula@intel.com> --- drivers/gpu/drm/i915/display/intel_display_core.h | 3 +++ .../gpu/drm/i915/display/intel_display_device.c | 13 +++++++++++++ drivers/gpu/drm/i915/i915_drv.h | 11 ++++++++++- drivers/gpu/drm/xe/xe_device_types.h | 15 +++++++++++++-- 4 files changed, 39 insertions(+), 3 deletions(-)