linux/drivers/gpu
Oscar Mateo 821d66dd7c drm/i915: Emphasize that ctx->id is merely a user handle
This is an Execlists preparatory patch, since they make context ID become an
overloaded term:

- In the software, it was used to distinguish which context userspace was
  trying to use.
- In the BSpec, the term is used to describe the 20-bits long field the
  hardware uses to it to discriminate the contexts that are submitted to
  the ELSP and inform the driver about their current status (via Context
  Switch Interrupts and Context Status Buffers).

Initially, I tried to make the different meanings converge, but it proved
impossible:

- The software ctx->id is per-filp, while the hardware one needs to be
  globally unique.
- Also, we multiplex several backing states objects per intel_context,
  and all of them need unique HW IDs.
- I tried adding a per-filp ID and then composing the HW context ID as:
  ctx->id + file_priv->id + ring->id, but the fact that the hardware only
  uses 20-bits means we have to artificially limit the number of filps or
  contexts the userspace can create.

The ctx->user_handle renaming bits are done with this Cocci patch (plus
manual frobbing of the struct declaration):

    @@
    struct intel_context c;
    @@
    - (c).id
    + c.user_handle

    @@
    struct intel_context *c;
    @@
    - (c)->id
    + c->user_handle

Also, while we are at it, s/DEFAULT_CONTEXT_ID/DEFAULT_CONTEXT_HANDLE and
change the type to unsigned 32 bits.

v2: s/handle/user_handle and change the type to uint32_t as suggested by
Chris Wilson.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v1)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-07-08 12:30:41 +02:00
..
drm drm/i915: Emphasize that ctx->id is merely a user handle 2014-07-08 12:30:41 +02:00
host1x gpu: host1x: Rename internal functions for clarity 2014-06-05 23:10:30 +02:00
ipu-v3 Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2014-06-12 11:32:30 -07:00
vga vgaswitcheroo: switch the mux to the igp on power down when runpm is enabled 2014-06-02 10:25:08 -04:00
Makefile gpu: ipu-v3: Move i.MX IPUv3 core driver out of staging 2014-06-04 11:06:52 +02:00