From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Jarzmik Date: Sat, 08 Aug 2015 16:56:34 +0000 Subject: Re: [BUG, RFC] Different bitfields in documentation and driver Message-Id: <87zj21k9bx.fsf@belgarion.home> List-Id: References: <55C503A7.6020304@tul.cz> In-Reply-To: <55C503A7.6020304@tul.cz> (Petr Cvek's message of "Fri, 07 Aug 2015 21:14:47 +0200") MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org Petr Cvek writes: > Hello, > It seems that PXA2xx framebuffer has switched bitfields in nonstd definition (when using overlay). > > This: > > http://lxr.free-electrons.com/source/drivers/video/fbdev/pxafb.h#L80 > > versus this: > > http://lxr.free-electrons.com/source/Documentation/fb/pxafb.txt#L128 > > Should be this changed in documentation or in driver? I was able to find only > one use (in form of little outdated mplayer patch) and it fills both bitfields > with zero (so potential change in driver will not break it). I'd rather go for documentation. Not only the driver's way looks more pretty to me, but it also guarantees compatibility from the kernel side. > P.S. Lack of overlay2's use is probably caused by errata "E24: LCD: Enabling > Overlay 2 for YUV420 hangs LCD controller.", which is not workarounded in this > driver. It should be mentioned in documentation and/or code, because the only > way to start the LCD again is a full PXA SoC reset. Ok, do you know if this this true for all pxa variants and steppings or is this for only a subset of them ? Cheers. -- Robert From mboxrd@z Thu Jan 1 00:00:00 1970 From: robert.jarzmik@free.fr (Robert Jarzmik) Date: Sat, 08 Aug 2015 18:56:34 +0200 Subject: [BUG, RFC] Different bitfields in documentation and driver In-Reply-To: <55C503A7.6020304@tul.cz> (Petr Cvek's message of "Fri, 07 Aug 2015 21:14:47 +0200") References: <55C503A7.6020304@tul.cz> Message-ID: <87zj21k9bx.fsf@belgarion.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Petr Cvek writes: > Hello, > It seems that PXA2xx framebuffer has switched bitfields in nonstd definition (when using overlay). > > This: > > http://lxr.free-electrons.com/source/drivers/video/fbdev/pxafb.h#L80 > > versus this: > > http://lxr.free-electrons.com/source/Documentation/fb/pxafb.txt#L128 > > Should be this changed in documentation or in driver? I was able to find only > one use (in form of little outdated mplayer patch) and it fills both bitfields > with zero (so potential change in driver will not break it). I'd rather go for documentation. Not only the driver's way looks more pretty to me, but it also guarantees compatibility from the kernel side. > P.S. Lack of overlay2's use is probably caused by errata "E24: LCD: Enabling > Overlay 2 for YUV420 hangs LCD controller.", which is not workarounded in this > driver. It should be mentioned in documentation and/or code, because the only > way to start the LCD again is a full PXA SoC reset. Ok, do you know if this this true for all pxa variants and steppings or is this for only a subset of them ? Cheers. -- Robert