On 28/02/2022 10:35, Sebastian Andrzej Siewior wrote:
On 2022-02-28 10:10:48 [+0000], Tvrtko Ursulin wrote:
Hi,
Hi,
Could you paste a link to the queue of i915 patches pending for a quick
overview of how much work there is and in what areas?
Last post to the list:
https://https://lkml.kernel.org/r/.kernel.org/all/20211214140301.520464-1-bigeasy@xxxxxxxxxxxxx/
or if you look at the DRM section in
https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tree/patches/series?h=v5.17-rc6-rt10-patches#n156
Thanks!
you see:
0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch
0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch
Two for the display folks.
0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch
What do preempt_disable/enable do on PREEMPT_RT? Thinking if instead the
solution could be to always force the !ATOMIC path (for the whole
_wait_for_atomic macro) on PREEMPT_RT.
0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch
If the issue is only with certain trace points why disable all?
0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch
Didn't quite fully understand, why is this not fixable? Especially
thinking if the option of not blanket disabling all tracepoints in the
previous patch.
0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch
Not sure about why cond_resched was put between irq_work_queue and
irq_work_sync - would it not be like-for-like change to have the two
together? Commit message makes me think _queue already starts the
handler on x86 at least.
0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch
I think this is okay. The part after the unlock is serialized by the
tasklet already.
Slight doubt due the comment:
local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */
Makes me want to think about it harder but not now.
Another thing to check is if execlists_context_status_change still needs
the atomic notifier chain with this change.
0010-drm-i915-Drop-the-irqs_disabled-check.patch
LGTM.
Revert-drm-i915-Depend-on-PREEMPT_RT.patch
Okay.
And finally for this very patch (the thread I am replying to):
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
and you could view them from
https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tree/patches?h=v5.17-rc6-rt10-patches
Also, I assume due absence of ARCH_SUPPORTS_RT being defined by any arch,
that something more is not yet ready?
Correct. Looking at what I have queued for the next merge window I have
less than 20 patches (excluding i915 and printk) before ARCH_SUPPORTS_RT
can be enabled for x86-64.
Regards,
Tvrtko
Sebastian
