From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Lee Jones <lee@kernel.org>
Cc: Michael Tretter <m.tretter@pengutronix.de>,
Pavel Machek <pavel@kernel.org>, Dan Murphy <dmurphy@ti.com>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Pavel Machek <pavel@ucw.cz>,
linux-leds@vger.kernel.org, kernel@pengutronix.de,
Khalid Talash <ktalash@topcon.com>
Subject: Re: [PATCH] leds: multicolor: limit intensity to max_brightness of LED
Date: Fri, 6 Mar 2026 17:09:46 +0200 [thread overview]
Message-ID: <aaruOlCwePDD5WXc@ashevche-desk.local> (raw)
In-Reply-To: <20260306135505.GN183676@google.com>
On Fri, Mar 06, 2026 at 01:55:05PM +0000, Lee Jones wrote:
> On Thu, 05 Mar 2026, Andy Shevchenko wrote:
> > On Fri, Jan 23, 2026 at 11:13:24AM +0100, Michael Tretter wrote:
> > > According to Documentation/ABI/testing/sysfs-class-led-multicolor, the
> > > intensity should not exceed /sys/class/leds/<led>/max_brightness.
> > >
> > > The interface doesn't check the values and higher values may lead to
> > > unexpected color changes if the brightness is changed.
> > >
> > > Clamp the intensity value to max_brightness.
> >
> > This also brings a regression if somebody doesn't care about wrapping around.
> > It's possible to return an error instead, but still the user space will be
> > broken (in some rare weird cases).
> >
> > Again, I care even less about this change, but be always careful,
> > the main rule in the kernel "We do NOT break user space".
>
> I'm going to remove this patch for now.
Wow, it was even never compiled!
For sure, please drop it.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-03-06 15:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-23 10:13 [PATCH] leds: multicolor: limit intensity to max_brightness of LED Michael Tretter
2026-02-05 15:51 ` (subset) " Lee Jones
2026-03-05 14:08 ` Andy Shevchenko
2026-03-06 11:30 ` Lee Jones
2026-03-06 15:08 ` Andy Shevchenko
2026-03-06 13:55 ` Lee Jones
2026-03-06 15:09 ` Andy Shevchenko [this message]
2026-03-06 15:34 ` Michael Tretter
2026-03-06 15:29 ` Michael Tretter
2026-03-06 18:58 ` Andy Shevchenko
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