Messages in this thread | | | From | David Binderman <> | Subject | Re: drivers/gpu/drm/bridge/fsl-ldb.c:101: possible loss of information. | Date | Thu, 9 Mar 2023 09:42:54 +0000 |
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Hello there Laurent,
>Would you be able to send a patch to fix this ?
Sadly, no. My success rate with kernel patches is low enough to make it not worth trying.
Regards
David Binderman
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Sent: 09 March 2023 09:26 To: David Binderman <dcb314@hotmail.com> Cc: andrzej.hajda@intel.com <andrzej.hajda@intel.com>; neil.armstrong@linaro.org <neil.armstrong@linaro.org>; rfoss@kernel.org <rfoss@kernel.org>; jonas@kwiboo.se <jonas@kwiboo.se>; jernej.skrabec@gmail.com <jernej.skrabec@gmail.com>; airlied@gmail.com <airlied@gmail.com>; daniel@ffwll.ch <daniel@ffwll.ch>; dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>; linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org> Subject: Re: drivers/gpu/drm/bridge/fsl-ldb.c:101: possible loss of information. Hi David,
On Thu, Mar 09, 2023 at 07:59:34AM +0000, David Binderman wrote: > Hello there Laurent, > > >We could, but I don't think it will make any difference in practice as > >the maximum pixel clock frequency supported by the SoC is 80MHz (per > >LVDS channel). That would result in a 560MHz frequency returned by this > >function, well below the 31 bits limit. > > Thanks for your explanation. I have a couple of suggestions for possible improvements: > > 1. Your explanatory text in a comment nearby. This helps all readers of the code. > > 2. Might the frequency go up to 300 MHz anytime soon ? The code will stop working then. > In this case, I would suggest to put in a run time sanity check to make sure no 31 bit overflow.
As it's a hardware limit of the SoC, I wouldn't expect so.
This being said, I think adding a UL suffix to the constants would be better than a comment as it will please static checkers and serve as documentation to humans. Would you be able to send a patch to fix this ?
> Just a couple of ideas for the code.
Thanks for taking the time to share those.
-- Regards,
Laurent Pinchart
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