From mboxrd@z Thu Jan 1 00:00:00 1970 From: Enric Balletbo i Serra Date: Mon, 19 Mar 2018 18:28:55 +0000 Subject: Re: [RESEND PATCH v5 1/5] pwm-backlight: enable/disable the PWM before/after LCD enable toggle. Message-Id: List-Id: References: <20180216174034.15936-1-enric.balletbo@collabora.com> <20180319165829.GB22770@ulmo> In-Reply-To: <20180319165829.GB22770@ulmo> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Thierry Reding Cc: linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Daniel Thompson , Heiko Stuebner , Bartlomiej Zolnierkiewicz , Jingoo Han , linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Herring , Richard Purdie , Jacek Anaszewski , Pavel Machek , groeck-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, kernel-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org, Lee Jones Hi Thierry, Thanks for your ack. On 19/03/18 17:58, Thierry Reding wrote: > On Fri, Feb 16, 2018 at 06:40:30PM +0100, Enric Balletbo i Serra wrote: >> Before this patch the enable signal was set before the PWM signal and >> vice-versa on power off. This sequence is wrong, at least, it is on >> the different panels datasheets that I checked, so I inverted the sequence >> to follow the specs. >> >> For reference the following panels have the mentioned sequence: >> - N133HSE-EA1 (Innolux) >> - N116BGE (Innolux) >> - N156BGE-L21 (Innolux) >> - B101EAN0 (Auo) >> - B101AW03 (Auo) >> - LTN101NT05 (Samsung) >> - CLAA101WA01A (Chunghwa) >> >> Signed-off-by: Enric Balletbo i Serra >> Acked-by: Daniel Thompson >> Acked-by: Jingoo Han >> --- >> Changes since v4: >> - Rebase on top of mainline. >> - Add the acks from Daniel Thompson and Jingoo Han. >> Changes since v3: >> - List the part numbers for the panel checked (Daniel Thompson) >> Changes since v2: >> - Add this as a separate patch (Thierry Reding) >> Changes since v1: >> - None >> >> drivers/video/backlight/pwm_bl.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) > > I'm surprised that panels even care about this. Do you see actual > breakage if these are the other way around? > At least the B116XTN02 requires enable first the PWM, wait 10ms and then BL_EN to avoid garbage. I did not observe the issue on other panels but the datasheets I checked specifies this sequence as correct. > Anyway, this seems to me as legit as the other way around, so: > > Acked-by: Thierry Reding >