CI has been sporadically reporting the following issue triggered by
igt@i915_selftest@live@hangcheck on ADL-P and similar machines:
<6> [414.049203] i915: Running intel_hangcheck_live_selftests/igt_reset_evict_fence
...
<6> [414.068804] i915 0000:00:02.0: [drm] GT0: GUC: submission enabled
<6> [414.068812] i915 0000:00:02.0: [drm] GT0: GUC: SLPC enabled
<3> [414.070354] Unable to pin Y-tiled fence; err:-4
<3> [414.071282] i915_vma_revoke_fence:301 GEM_BUG_ON(!i915_active_is_idle(&fence->active))
...
<4>[ 609.603992] ------------[ cut here ]------------
<2>[ 609.603995] kernel BUG at drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c:301!
<4>[ 609.604003] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
<4>[ 609.604006] CPU: 0 PID: 268 Comm: kworker/u64:3 Tainted: G U W 6.9.0-CI_DRM_14785-g1ba62f8cea9c+ #1
<4>[ 609.604008] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023
<4>[ 609.604010] Workqueue: i915 __i915_gem_free_work [i915]
<4>[ 609.604149] RIP: 0010:i915_vma_revoke_fence+0x187/0x1f0 [i915]
...
<4>[ 609.604271] Call Trace:
<4>[ 609.604273] <TASK>
...
<4>[ 609.604716] __i915_vma_evict+0x2e9/0x550 [i915]
<4>[ 609.604852] __i915_vma_unbind+0x7c/0x160 [i915]
<4>[ 609.604977] force_unbind+0x24/0xa0 [i915]
<4>[ 609.605098] i915_vma_destroy+0x2f/0xa0 [i915]
<4>[ 609.605210] __i915_gem_object_pages_fini+0x51/0x2f0 [i915]
<4>[ 609.605330] __i915_gem_free_objects.isra.0+0x6a/0xc0 [i915]
<4>[ 609.605440] process_scheduled_works+0x351/0x690
...
In the past, there were similar failures reported by CI from other IGT
tests, observed on other platforms.
Before commit 63baf4f3d5 ("drm/i915/gt: Only wait for GPU activity
before unbinding a GGTT fence"), i915_vma_revoke_fence() was waiting for
idleness of vma->active via fence_update(). That commit introduced
vma->fence->active in order for the fence_update() to be able to wait
selectively on that one instead of vma->active since only idleness of
fence registers was needed. But then, another commit 0d86ee3509
("drm/i915/gt: Make fence revocation unequivocal") replaced the call to
fence_update() in i915_vma_revoke_fence() with only fence_write(), and
also added that GEM_BUG_ON(!i915_active_is_idle(&fence->active)) in front.
No justification was provided on why we might then expect idleness of
vma->fence->active without first waiting on it.
The issue can be potentially caused by a race among revocation of fence
registers on one side and sequential execution of signal callbacks invoked
on completion of a request that was using them on the other, still
processed in parallel to revocation of those fence registers. Fix it by
waiting for idleness of vma->fence->active in i915_vma_revoke_fence().
Fixes: 0d86ee3509 ("drm/i915/gt: Make fence revocation unequivocal")
Closes: https://gitlab.freedesktop.org/drm/intel/issues/10021
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: stable@vger.kernel.org # v5.8+
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240603195446.297690-2-janusz.krzysztofik@linux.intel.com
The whole point of the previous fixes has been to change the CCS
hardware configuration to generate only one stream available to
the compute users. We did this by changing the info.engine_mask
that is set during device probe, reset during the detection of
the fused engines, and finally reset again when choosing the CCS
mode.
We can't use the engine_mask variable anymore, as with the
current configuration, it imposes only one CCS no matter what the
hardware configuration is.
Before changing the engine_mask for the third time, save it and
use it for calculating the CCS mode.
After the previous changes, the user reported a performance drop
to around 1/4. We have tested that the compute operations, with
the current patch, have improved by the same factor.
Fixes: 6db31251bb ("drm/i915/gt: Enable only one CCS for compute workload")
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Chris Wilson <chris.p.wilson@linux.intel.com>
Cc: Gnattu OC <gnattuoc@me.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Tested-by: Jian Ye <jian.ye@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Tested-by: Gnattu OC <gnattuoc@me.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517090616.242529-1-andi.shyti@linux.intel.com
With gcc-7 and earlier, there are lots of warnings like
In file included from <command-line>:0:0:
In function '__guc_context_policy_add_priority.isra.66',
inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
...
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
^~~~~~~~~~
Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.
Fixes: 77b6f79df6 ("drm/i915/guc: Update to GuC version 69.0.3")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Julia Filipchuk <julia.filipchuk@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240430164809.482131-1-julia.filipchuk@intel.com
When debugging GPU hangs Mesa developers are finding it useful to replay
the captured error state against the simulator. But due various simulator
limitations which prevent replicating all hangs, one step further is being
able to replay against a real GPU.
This is almost doable today with the missing part being able to upload the
captured context image into the driver state prior to executing the
uploaded hanging batch and all the buffers.
To enable this last part we add a new context parameter called
I915_CONTEXT_PARAM_CONTEXT_IMAGE. It follows the existing SSEU
configuration pattern of being able to select which context to apply
against, paired with the actual image and its size.
Since this is adding a new concept of debug only uapi, we hide it behind
a new kconfig option and also require activation with a module parameter.
Together with a warning banner printed at driver load, all those combined
should be sufficient to guard against inadvertently enabling the feature.
In terms of implementation we allow the legacy context set param to be
used since that removes the need to record the per context data in the
proto context, while still allowing flexibility of specifying context
images for any context.
Mesa MR using the uapi can be seen at:
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27594
v2:
* Fix whitespace alignment as per checkpatch.
* Added warning on userspace misuse.
* Rebase for extracting ce->default_state shadowing.
v3:
* Rebase for I915_CONTEXT_PARAM_LOW_LATENCY.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Carlos Santa <carlos.santa@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: Carlos Santa <carlos.santa@intel.com>
Signed-off-by: Tvrtko Ursulin <tursulin@igalia.com>
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20240514145939.87427-2-tursulin@igalia.com
Problem statement: During the system boot time, an application request
for the bulk volume of cleared range bias memory when the clear_avail
is zero, we dont fallback into normal allocation method as we had an
unnecessary clear_avail check which prevents the fallback method leads
to fb allocation failure following system goes into unresponsive state.
Solution: Remove the unnecessary clear_avail check in the range bias
allocation function.
v2: add a kunit for this corner case (Daniel Vetter)
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Fixes: 96950929eb ("drm/buddy: Implement tracking clear page feature")
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240514145636.16253-1-Arunpravin.PaneerSelvam@amd.com
The breadcrumbs use a GT wakeref for guarding the interrupt, but are
disarmed during release of the engine wakeref. This leaves a hole where
we may attach a breadcrumb just as the engine is parking (after it has
parked its breadcrumbs), execute the irq worker with some signalers still
attached, but never be woken again.
That issue manifests itself in CI with IGT runner timeouts while tests
are waiting indefinitely for release of all GT wakerefs.
<6> [209.151778] i915: Running live_engine_pm_selftests/live_engine_busy_stats
<7> [209.231628] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_5
<7> [209.231816] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_4
<7> [209.231944] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_3
<7> [209.232056] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_2
<7> [209.232166] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling DC_off
<7> [209.232270] i915 0000:00:02.0: [drm:skl_enable_dc6 [i915]] Enabling DC6
<7> [209.232368] i915 0000:00:02.0: [drm:gen9_set_dc_state.part.0 [i915]] Setting DC state from 00 to 02
<4> [299.356116] [IGT] Inactivity timeout exceeded. Killing the current test with SIGQUIT.
...
<6> [299.356526] sysrq: Show State
...
<6> [299.373964] task:i915_selftest state:D stack:11784 pid:5578 tgid:5578 ppid:873 flags:0x00004002
<6> [299.373967] Call Trace:
<6> [299.373968] <TASK>
<6> [299.373970] __schedule+0x3bb/0xda0
<6> [299.373974] schedule+0x41/0x110
<6> [299.373976] intel_wakeref_wait_for_idle+0x82/0x100 [i915]
<6> [299.374083] ? __pfx_var_wake_function+0x10/0x10
<6> [299.374087] live_engine_busy_stats+0x9b/0x500 [i915]
<6> [299.374173] __i915_subtests+0xbe/0x240 [i915]
<6> [299.374277] ? __pfx___intel_gt_live_setup+0x10/0x10 [i915]
<6> [299.374369] ? __pfx___intel_gt_live_teardown+0x10/0x10 [i915]
<6> [299.374456] intel_engine_live_selftests+0x1c/0x30 [i915]
<6> [299.374547] __run_selftests+0xbb/0x190 [i915]
<6> [299.374635] i915_live_selftests+0x4b/0x90 [i915]
<6> [299.374717] i915_pci_probe+0x10d/0x210 [i915]
At the end of the interrupt worker, if there are no more engines awake,
disarm the breadcrumb and go to sleep.
Fixes: 9d5612ca16 ("drm/i915/gt: Defer enabling the breadcrumb interrupt to after submission")
Closes: https://gitlab.freedesktop.org/drm/intel/issues/10026
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: <stable@vger.kernel.org> # v5.12+
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Acked-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240423165505.465734-2-janusz.krzysztofik@linux.intel.com
Updates for v6.10
Core:
- Switched to generating register header files during build process
instead of shipping pre-generated headers
- Merged DPU and MDP4 format databases.
DP:
- Stop using compat string to distinguish DP and eDP cases
- Added support for X Elite platform (X1E80100)
- Reworked DP aux/audio support
- Added SM6350 DP to the bindings (no driver changes, using SM8350
as a fallback compat)
GPU:
- a7xx perfcntr reg fixes
- MAINTAINERS updates
- a750 devcoredump support
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGtpw6dNR9JBikFTQ=TCpt-9FeFW+SGjXWv+Jv3emm0Pbg@mail.gmail.com
This reverts commit 1f33dc0c11.
There was a patch supposed to fix an issue of illegal attempts to free a
still active i915 VMA object when parking a GT believed to be idle,
reported by CI on 2-GT Meteor Lake. As a solution, an extra wakeref for
a Primary GT was acquired from i915_gem_do_execbuffer() -- see commit
f56fe3e917 ("drm/i915: Fix a VMA UAF for multi-gt platform").
However, that fix occurred insufficient -- the issue was still reported by
CI. That wakeref was released on exit from i915_gem_do_execbuffer(), then
potentially before completion of the request and deactivation of its
associated VMAs. Moreover, CI reports indicated that single-GT platforms
also suffered sporadically from the same race.
Since that issue was fixed by another commit f3c71b2ded ("drm/i915/vma:
Fix UAF on destroy against retire race"), the changes introduced by that
insufficient fix were dropped as no longer useful. However, that series
resulted in another VMA UAF scenario now being triggered in CI.
<4> [260.290809] ------------[ cut here ]------------
<4> [260.290988] list_del corruption. prev->next should be ffff888118c5d990, but was ffff888118c5a510. (prev=ffff888118c5a510)
<4> [260.291004] WARNING: CPU: 2 PID: 1143 at lib/list_debug.c:62 __list_del_entry_valid_or_report+0xb7/0xe0
..
<4> [260.291055] CPU: 2 PID: 1143 Comm: kms_plane Not tainted 6.9.0-rc2-CI_DRM_14524-ga25d180c6853+ #1
<4> [260.291058] Hardware name: Intel Corporation Meteor Lake Client Platform/MTL-P LP5x T3 RVP, BIOS MTLPFWI1.R00.3471.D91.2401310918 01/31/2024
<4> [260.291060] RIP: 0010:__list_del_entry_valid_or_report+0xb7/0xe0
...
<4> [260.291087] Call Trace:
<4> [260.291089] <TASK>
<4> [260.291124] i915_vma_reopen+0x43/0x80 [i915]
<4> [260.291298] eb_lookup_vmas+0x9cb/0xcc0 [i915]
<4> [260.291579] i915_gem_do_execbuffer+0xc9a/0x26d0 [i915]
<4> [260.291883] i915_gem_execbuffer2_ioctl+0x123/0x2a0 [i915]
...
<4> [260.292301] </TASK>
...
<4> [260.292506] ---[ end trace 0000000000000000 ]---
<4> [260.292782] general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6ca3: 0000 [#1] PREEMPT SMP NOPTI
<4> [260.303575] CPU: 2 PID: 1143 Comm: kms_plane Tainted: G W 6.9.0-rc2-CI_DRM_14524-ga25d180c6853+ #1
<4> [260.313851] Hardware name: Intel Corporation Meteor Lake Client Platform/MTL-P LP5x T3 RVP, BIOS MTLPFWI1.R00.3471.D91.2401310918 01/31/2024
<4> [260.326359] RIP: 0010:eb_validate_vmas+0x114/0xd80 [i915]
...
<4> [260.428756] Call Trace:
<4> [260.431192] <TASK>
<4> [639.283393] i915_gem_do_execbuffer+0xd05/0x26d0 [i915]
<4> [639.305245] i915_gem_execbuffer2_ioctl+0x123/0x2a0 [i915]
...
<4> [639.411134] </TASK>
...
<4> [639.449979] ---[ end trace 0000000000000000 ]---
We defer actually closing, unbinding and destroying a VMA until next idle
point, or until the object is freed in the meantime. By postponing the
unbind, we allow for the VMA to be reopened by the client, avoiding the
work required to rebind the VMA.
Starting from commit b0647a5e79 ("drm/i915: Avoid live-lock with
i915_vma_parked()"), we assume that as long as a GT is held idle, no VMA
would be reopened while we destroy them. That assumption is no longer
true in multi-GT configurations, where a VMA we reopen may be handled by a
GT different from the one that we already keep active via its engine while
we set up an execbuf request.
Restoring the extra GT0 PM wakeref removed from i915_gem_do_execbuffer()
processing path seems to fix this issue.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10608
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Nirmoy Das <nirmoy.das@linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@linux.intel.com>
Fixes: 1f33dc0c11 ("drm/i915: Remove extra multi-gt pm-references")
Link: https://patchwork.freedesktop.org/patch/msgid/20240506180253.96858-2-janusz.krzysztofik@linux.intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
These tables were made non-const in commit 3cba4a2cdf ("drm/msm/a6xx:
Update ROQ size in coredump") in order to avoid powering up the GPU when
reading back a devcoredump. Instead let's just stash the count that is
potentially read from hw in struct a6xx_gpu_state_obj, and make the
tables const again.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/592699/
The msm driver is.. gigantic and covers display hardware (incl. things
concerning (e)DP, DSI, HDMI), as well as the entire lineup of Adreno
GPUs (with hw bringup, memory mappings, userspace interaction etc.).
Because of that, people listed as M:/R: receive patches concerning
drivers for any part of the display block OR the GPU. Separate the
latter, as it's both a functionally separate block and is of
interest to different folks.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/590704/
Signed-off-by: Rob Clark <robdclark@chromium.org>
Calling a6xx_destroy() before adreno_gpu_init() leads to a null pointer
dereference on:
msm_gpu_cleanup() : platform_set_drvdata(gpu->pdev, NULL);
as gpu->pdev is only assigned in:
a6xx_gpu_init()
|_ adreno_gpu_init
|_ msm_gpu_init()
Instead of relying on handwavy null checks down the cleanup chain,
explicitly de-allocate the LLC data and free a6xx_gpu instead.
Fixes: 76efc2453d ("drm/msm/gpu: Fix crash during system suspend after unbind")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/588919/
Signed-off-by: Rob Clark <robdclark@chromium.org>
In addition to the CP_PERFCTR_CP_SEL register range, allow writes to the
CP_BV_PERFCTR_CP_SEL registers in the 0x8e0-0x8e6 range for profiling
purposes of tools like fdperf and perfetto.
Signed-off-by: Zan Dobersek <zdobersek@igalia.com>
Patchwork: https://patchwork.freedesktop.org/patch/580548/
[fixup a730_protect size]
Signed-off-by: Rob Clark <robdclark@chromium.org>
This reverts commit 8a91b29f1f.
The regulator_disable() added by the original commit solves one kind of
regulator imbalance but adds another one as it allows the regulator to be
disabled one more time than it is enabled in the following scenario:
1. Start video pipeline -> sn65dsi83_atomic_pre_enable -> regulator_enable
2. PLL lock fails -> regulator_disable
3. Stop video pipeline -> sn65dsi83_atomic_disable -> regulator_disable
The reason is clear from the code flow, which looks like this (after
removing unrelated code):
static void sn65dsi83_atomic_pre_enable()
{
regulator_enable(ctx->vcc);
if (PLL failed locking) {
regulator_disable(ctx->vcc); <---- added by patch being reverted
return;
}
}
static void sn65dsi83_atomic_disable()
{
regulator_disable(ctx->vcc);
}
The use case for introducing the additional regulator_disable() was
removing the module for debugging (see link below for the discussion). If
the module is removed after a .atomic_pre_enable, i.e. with an active
pipeline from the DRM point of view, .atomic_disable is not called and thus
the regulator would not be disabled.
According to the discussion however there is no actual use case for
removing the module with an active pipeline, except for
debugging/development.
On the other hand, the occurrence of a PLL lock failure is possible due to
any physical reason (e.g. a temporary hardware failure for electrical
reasons) so handling it gracefully should be supported. As there is no way
for .atomic[_pre]_enable to report an error to the core, the only clean way
to support it is calling regulator_disabled() only in .atomic_disable,
unconditionally, as it was before.
Link: https://lore.kernel.org/all/15244220.uLZWGnKmhe@steina-w/
Fixes: 8a91b29f1f ("drm/bridge: ti-sn65dsi83: Fix enable error path")
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426122259.46808-1-luca.ceresoli@bootlin.com
(cherry picked from commit 2940ee03b2)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
When you create a submenu using the 'menu' syntax, there is no
ambiguity about its end because the code between 'menu' and 'endmenu'
becomes the submenu.
In contrast, 'menuconfig' does not have the corresponding end marker.
Instead, the end of the submenu is inferred from symbol dependencies.
This is detailed in Documentation/kbuild/kconfig-language.rst, starting
line 348. It outlines two methods to place the code under the submenu:
(1) Open an if-block immediately after 'menuconfig', enclosing the
submenu content within it
(2) Add 'depends on' to every symbol intended for the submenu
Many subsystems opt for (1) because it reliably maintains the submenu
structure.
The DRM subsystem adopts (2). The submenu ends when the sequence of
'depends on DRM' breaks. It can be confirmed by running a GUI frontend
such as 'make menuconfig' and visiting the DRM menu:
< > Direct Rendering Manager (XFree86 4.1.0 and higher DRI support) ----
If you toggle this, you will notice most of the DRM-related options
appear below it, not in the submenu.
I highly recommend the approach (1). Obviously, (2) is not reliable,
as the submenu breaks whenever someone forgets to add 'depends on DRM'.
This commit encloses the entire DRM configuration with 'if DRM' and
'endif', except for DRM_PANEL_ORIENTATION_QUIRKS.
Note:
Now, 'depends on DRM' properties inside the if-block are all redundant.
I leave it as follow-up cleanups.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426135602.2500125-1-masahiroy@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>