One of the recent changes introduced a warning about
undefined behavior in the sanity checking:
drivers/gpu/drm/i915/intel_ddi.c: In function 'intel_ddi_hdmi_level':
drivers/gpu/drm/i915/intel_ddi.c:654:6: error: 'n_hdmi_entries' may be used uninitialized in this function [-Werror=maybe-uninitialized]
It seems that the new cnl specific get_buf_trans functions
can return uninitialized data if the voltage level is set
to an unexpected value. This changes the code to always return
'1' in that error case, which seems like the safest choice
as we use one less than the number as an array index later on.
Fixes: cc9cabfdec ("drm/i915/cnl: Move voltage check into ddi buf trans functions.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[danvet: shut up gcc comment added.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171005120835.437022-1-arnd@arndb.de
An earlier bugfix tried to work around this build failure:
drivers/gpu/drm/i915/selftests/mock_gem_device.c: In function 'mock_gem_device':
drivers/gpu/drm/i915/selftests/mock_gem_device.c:151:20: error: 'struct dev_archdata' has no member named 'iommu'
Checking for CONFIG_IOMMU_API is not sufficient as a compile-time
test since that may be enabled in configurations that have neither
INTEL_IOMMU not AMD_IOMMU enabled. This changes the check to
INTEL_IOMMU instead, as this is the only case we actually care about.
Fixes: f46f156ea7 ("drm/i915/selftests: Only touch archdata.iommu when it exists")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171005120749.400818-1-arnd@arndb.de
Use a priority stored in the context as the initial value when
submitting a request. This allows us to change the default priority on a
per-context basis, allowing different contexts to be favoured with GPU
time at the expense of lower importance work. The user can adjust the
context's priority via I915_CONTEXT_PARAM_PRIORITY, with more positive
values being higher priority (they will be serviced earlier, after their
dependencies have been resolved). Any prerequisite work for an execbuf
will have its priority raised to match the new request as required.
Normal users can specify any value in the range of -1023 to 0 [default],
i.e. they can reduce the priority of their workloads (and temporarily
boost it back to normal if so desired).
Privileged users can specify any value in the range of -1023 to 1023,
[default is 0], i.e. they can raise their priority above all overs and
so potentially starve the system.
Note that the existing schedulers are not fair, nor load balancing, the
execution is strictly by priority on a first-come, first-served basis,
and the driver may choose to boost some requests above the range
available to users.
This priority was originally based around nice(2), but evolved to allow
clients to adjust their priority within a small range, and allow for a
privileged high priority range.
For example, this can be used to implement EGL_IMG_context_priority
https://www.khronos.org/registry/egl/extensions/IMG/EGL_IMG_context_priority.txt
EGL_CONTEXT_PRIORITY_LEVEL_IMG determines the priority level of
the context to be created. This attribute is a hint, as an
implementation may not support multiple contexts at some
priority levels and system policy may limit access to high
priority contexts to appropriate system privilege level. The
default value for EGL_CONTEXT_PRIORITY_LEVEL_IMG is
EGL_CONTEXT_PRIORITY_MEDIUM_IMG."
so we can map
PRIORITY_HIGH -> 1023 [privileged, will failback to 0]
PRIORITY_MED -> 0 [default]
PRIORITY_LOW -> -1023
They also map onto the priorities used by VkQueue (and a VkQueue is
essentially a timeline, our i915_gem_context under full-ppgtt).
v2: s/CAP_SYS_ADMIN/CAP_SYS_NICE/
v3: Report min/max user priorities as defines in the uapi, and rebase
internal priorities on the exposed values.
Testcase: igt/gem_exec_schedule
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-9-chris@chris-wilson.co.uk
When we write to ELSP, it triggers a context preemption at the earliest
arbitration point (3DPRIMITIVE, some PIPECONTROLs, a few other
operations and the explicit MI_ARB_CHECK). If this is to the same
context, it triggers a LITE_RESTORE where the RING_TAIL is merely
updated (used currently to chain requests from the same context
together, avoiding bubbles). However, if it is to a different context, a
full context-switch is performed and it will start to execute the new
context saving the image of the old for later execution.
Previously we avoided preemption by only submitting a new context when
the old was idle. But now we wish embrace it, and if the new request has
a higher priority than the currently executing request, we write to the
ELSP regardless, thus triggering preemption, but we tell the GPU to
switch to our special preemption context (not the target). In the
context-switch interrupt handler, we know that the previous contexts
have finished execution and so can unwind all the incomplete requests
and compute the new highest priority request to execute.
It would be feasible to avoid the switch-to-idle intermediate by
programming the ELSP with the target context. The difficulty is in
tracking which request that should be whilst maintaining the dependency
change, the error comes in with coalesced requests. As we only track the
most recent request and its priority, we may run into the issue of being
tricked in preempting a high priority request that was followed by a
low priority request from the same context (e.g. for PI); worse still
that earlier request may be our own dependency and the order then broken
by preemption. By injecting the switch-to-idle and then recomputing the
priority queue, we avoid the issue with tracking in-flight coalesced
requests. Having tried the preempt-to-busy approach, and failed to find
a way around the coalesced priority issue, Michal's original proposal to
inject an idle context (based on handling GuC preemption) succeeds.
The current heuristic for deciding when to preempt are only if the new
request is of higher priority, and has the privileged priority of
greater than 0. Note that the scheduler remains unfair!
v2: Disable for gen8 (bdw/bsw) as we need additional w/a for GPGPU.
Since, the feature is now conditional and not always available when we
have a scheduler, make it known via the HAS_SCHEDULER GETPARAM (now a
capability mask).
v3: Stylistic tweaks.
v4: Appease Joonas with a snippet of kerneldoc, only to fuel to fire of
the preempt vs preempting debate.
Suggested-by: Michal Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-8-chris@chris-wilson.co.uk
In the next few patches, we wish to enable different features for the
scheduler, some which may subtlety change ABI (e.g. allow requests to be
reordered under different circumstances). So we need to make sure
userspace is cognizant of the changes (if they care), by which we employ
the usual method of a GETPARAM. We already have an
I915_PARAM_HAS_SCHEDULER (which notes the existing ability to reorder
requests to avoid bubbles), and now we wish to extend that to be a
bitmask to describe the different capabilities implemented.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-7-chris@chris-wilson.co.uk
With preemption, we will want to "unsubmit" a request, taking it back
from the hw and returning it to the priority sorted execution list. In
order to know where to insert it into that list, we need to remember
its adjust priority (which may change even as it was being executed).
This also affects reset for execlists as we are now unsubmitting the
requests following the reset (rather than directly writing the ELSP for
the inflight contexts). This turns reset into an accidental preemption
point, as after the reset we may choose a different pair of contexts to
submit to hw.
GuC is not updated as this series doesn't add preemption to the GuC
submission, and so it can keep benefiting from the early pruning of the
DFS inside execlists_schedule() for a little longer. We also need to
find a way of reducing the cost of that DFS...
v2: Include priority in error-state
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-6-chris@chris-wilson.co.uk
Add another perma-pinned context for using for preemption at any time.
We cannot just reuse the existing kernel context, as first and foremost
we need to ensure that we can preempt the kernel context itself, so
require a distinct context id. Similar to the kernel context, we may
want to interrupt execution and switch to the preempt context at any
time, and so it needs to be permanently pinned and available.
To compensate for yet another permanent allocation, we shrink the
existing context and the new context by reducing their ringbuffer to the
minimum.
v2: Assert that we never allocate a request from the preemption context.
v3: Limit perma-pin to engines that may preempt.
v4: Onion cleanup for early driver death
v5: Onion ordering in main driver cleanup as well.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-4-chris@chris-wilson.co.uk
Supporting fine-granularity preemption levels may require changes in
userspace batch buffer programming. Therefore, we need to fallback to
safe default values, rather that use hardware defaults. Userspace is
still able to enable fine-granularity, since we're whitelisting the
register controlling it in WaEnablePreemptionGranularityControlByUMD.
v2: Extend w/a to cover Cannonlake
v3: Fix commentary to include both fake w/a names.
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-2-chris@chris-wilson.co.uk
The common lane power down flag of a DPIO PHY has a funky semantic:
after the initial enabling of the PHY (so from a disabled state) this
flag will be clear. It will be set only after the PHY will be used for
the first time (for instance due to enabling the corresponding pipe) and
then become unused (due to disabling the pipe). During the initial PHY
enablement we don't know which of the above phases we are in, so move
the check for the flag where this is known, the HW readout code. This is
where the rest of lane power down status checks are done anyway.
This fixes at least a problem on GLK where after module reloading, the
common lane power down flag of PHY1 is set, but the PHY is actually
powered-on and properly set up. The GRC readout code for other PHYs will
hence think that PHY1 is not powered initially and disable it after the
GRC readout. This will cause the AUX power well related to PHY1 to get
disabled in a stuck state, timing out when we try to enable it later.
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Fixes: e93da0a013 ("drm/i915/bxt: Sanitiy check the PHY lane power down status")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102777
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171002135307.26117-1-imre.deak@intel.com
(cherry picked from commit e19c1eb885)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
