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Goncalves" To: Sebastian Andrzej Siewior Cc: Steven Rostedt , Stable RT List Subject: Re: Question about the maintenance of OOT RT patches for LTS releases (v12.x and v18.x) Message-ID: References: <20260624064944.Lt3vOksN@linutronix.de> Precedence: bulk X-Mailing-List: stable-rt@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260624064944.Lt3vOksN@linutronix.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On Wed, Jun 24, 2026 at 08:49:44AM +0200, Sebastian Andrzej Siewior wrote: > On 2026-06-22 13:11:59 [-0300], Luis Claudio R. Goncalves wrote: > > Hello! > > > > The question is simple: > > > > Should we have somebody maintaining the OOT RT patches for v12.x and v18.x, > > the LTS versions that already have PREEMPT_RT in-tree? > > > > As we still have a few OOT patches, after a while, people using PREEMPT_RT on > > those versions may encounter conflicts trying to apply the old patches. And > > as those patches are not in-tree, the fixes won't probably be routed via > > Stable. > > For 6.18, we have: > - 8250 console > - i915 > - arm-32 > - powerpc > > For 6.12, we have additionally > - ktimers thread > - the whole lazy-preempt I need to correct myself here, our local hero Daniel Wagner is maintaining the v6.12-rt version. Sorry for that :) Sebastian, just to make sure I understood your answer, then we don't need to keep the OOT patches up-to-date for v6.18-rt specifically? My question came from comments raised on the last two RT maintainers meetings and the LF RT Board meeting. I just want to have a good answer if somebody else asks about that. And to volunteer if work is needed. Best, Luis > So for v6.12 there are bits outstanding which can impact you. > For v6.18 if you are on arm64 then the mainline version is slightly > better than on x86 because on arm64 you might be using the pl011 UART > which has nbcon support since v6.15 while on x86 you almost always have > the 8250 which is not yet with nbcon support in-tree. > > These are the missing bits. None of them are essential. If you on x86 > and your kernel crashes, it is more likely to see a backtrace with nbcon > driver than without it. > > > Best regards, > > Luis > > Sebastian > ---end quoted text---