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Wed, 11 Dec 2024 01:04:39 +0100 Message-ID: <1c72c520-64cc-436e-aa74-970b30cef593@gmx.de> Date: Wed, 11 Dec 2024 01:04:39 +0100 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] fbdev: Fix recursive dependencies wrt BACKLIGHT_CLASS_DEVICE From: Helge Deller To: Thomas Zimmermann , javierm@redhat.com, arnd@arndb.de, simona@ffwll.ch, airlied@gmail.com Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-staging@lists.linux.dev, linuxppc-dev@lists.ozlabs.org References: <20241210142329.660801-1-tzimmermann@suse.de> <20241210142329.660801-2-tzimmermann@suse.de> <6b543ccd-23dd-474d-9828-1eb0ecec9c5d@gmx.de> Content-Language: en-US Autocrypt: addr=deller@gmx.de; keydata= xsFNBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/3smlClbeKkWT HLnjgkbPFDmcmCz5V0Wv1mKYRClAHPCIBIJgyICqqUZo2qGmKstUx3pFAiztlXBANpRECgwJ r+8w6mkccOM9GhoPU0vMaD/UVJcJQzvrxVHO8EHS36aUkjKd6cOpdVbCt3qx8cEhCmaFEO6u CL+k5AZQoABbFQEBocZE1/lSYzaHkcHrjn4cQjc3CffXnUVYwlo8EYOtAHgMDC39s9a7S90L 69l6G73lYBD/Br5lnDPlG6dKfGFZZpQ1h8/x+Qz366Ojfq9MuuRJg7ZQpe6foiOtqwKym/zV dVvSdOOc5sHSpfwu5+BVAAyBd6hw4NddlAQUjHSRs3zJ9OfrEx2d3mIfXZ7+pMhZ7qX0Axlq Lq+B5cfLpzkPAgKn11tfXFxP+hcPHIts0bnDz4EEp+HraW+oRCH2m57Y9zhcJTOJaLw4YpTY GRUlF076vZ2Hz/xMEvIJddRGId7UXZgH9a32NDf+BUjWEZvFt1wFSW1r7zb7oGCwZMy2LI/G aHQv/N0NeFMd28z+deyxd0k1CGefHJuJcOJDVtcE1rGQ43aDhWSpXvXKDj42vFD2We6uIo9D 1VNre2+uAxFzqqf026H6cH8hin9Vnx7p3uq3Dka/Y/qmRFnKVQARAQABzRxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+wsGRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA FiEERUSCKCzZENvvPSX4Pl89BKeiRgMFAl3J1zsCGQEACgkQPl89BKeiRgNK7xAAg6kJTPje uBm9PJTUxXaoaLJFXbYdSPfXhqX/BI9Xi2VzhwC2nSmizdFbeobQBTtRIz5LPhjk95t11q0s uP5htzNISPpwxiYZGKrNnXfcPlziI2bUtlz4ke34cLK6MIl1kbS0/kJBxhiXyvyTWk2JmkMi REjR84lCMAoJd1OM9XGFOg94BT5aLlEKFcld9qj7B4UFpma8RbRUpUWdo0omAEgrnhaKJwV8 qt0ULaF/kyP5qbI8iA2PAvIjq73dA4LNKdMFPG7Rw8yITQ1Vi0DlDgDT2RLvKxEQC0o3C6O4 iQq7qamsThLK0JSDRdLDnq6Phv+Yahd7sDMYuk3gIdoyczRkXzncWAYq7XTWl7nZYBVXG1D8 gkdclsnHzEKpTQIzn/rGyZshsjL4pxVUIpw/vdfx8oNRLKj7iduf11g2kFP71e9v2PP94ik3 Xi9oszP+fP770J0B8QM8w745BrcQm41SsILjArK+5mMHrYhM4ZFN7aipK3UXDNs3vjN+t0zi qErzlrxXtsX4J6nqjs/mF9frVkpv7OTAzj7pjFHv0Bu8pRm4AyW6Y5/H6jOup6nkJdP/AFDu 5ImdlA0jhr3iLk9s9WnjBUHyMYu+HD7qR3yhX6uWxg2oB2FWVMRLXbPEt2hRGq09rVQS7DBy dbZgPwou7pD8MTfQhGmDJFKm2jvOwU0EXchrcwEQAOsDQjdtPeaRt8EP2pc8tG+g9eiiX9Sh rX87SLSeKF6uHpEJ3VbhafIU6A7hy7RcIJnQz0hEUdXjH774B8YD3JKnAtfAyuIU2/rOGa/v UN4BY6U6TVIOv9piVQByBthGQh4YHhePSKtPzK9Pv/6rd8H3IWnJK/dXiUDQllkedrENXrZp eLUjhyp94ooo9XqRl44YqlsrSUh+BzW7wqwfmu26UjmAzIZYVCPCq5IjD96QrhLf6naY6En3 ++tqCAWPkqKvWfRdXPOz4GK08uhcBp3jZHTVkcbo5qahVpv8Y8mzOvSIAxnIjb+cklVxjyY9 dVlrhfKiK5L+zA2fWUreVBqLs1SjfHm5OGuQ2qqzVcMYJGH/uisJn22VXB1c48yYyGv2HUN5 lC1JHQUV9734I5cczA2Gfo27nTHy3zANj4hy+s/q1adzvn7hMokU7OehwKrNXafFfwWVK3OG 1dSjWtgIv5KJi1XZk5TV6JlPZSqj4D8pUwIx3KSp0cD7xTEZATRfc47Yc+cyKcXG034tNEAc xZNTR1kMi9njdxc1wzM9T6pspTtA0vuD3ee94Dg+nDrH1As24uwfFLguiILPzpl0kLaPYYgB wumlL2nGcB6RVRRFMiAS5uOTEk+sJ/tRiQwO3K8vmaECaNJRfJC7weH+jww1Dzo0f1TP6rUa fTBRABEBAAHCwXYEGAEIACAWIQRFRIIoLNkQ2+89Jfg+Xz0Ep6JGAwUCXchrcwIbDAAKCRA+ Xz0Ep6JGAxtdEAC54NQMBwjUNqBNCMsh6WrwQwbg9tkJw718QHPw43gKFSxFIYzdBzD/YMPH l+2fFiefvmI4uNDjlyCITGSM+T6b8cA7YAKvZhzJyJSS7pRzsIKGjhk7zADL1+PJei9p9idy RbmFKo0dAL+ac0t/EZULHGPuIiavWLgwYLVoUEBwz86ZtEtVmDmEsj8ryWw75ZIarNDhV74s BdM2ffUJk3+vWe25BPcJiaZkTuFt+xt2CdbvpZv3IPrEkp9GAKof2hHdFCRKMtgxBo8Kao6p Ws/Vv68FusAi94ySuZT3fp1xGWWf5+1jX4ylC//w0Rj85QihTpA2MylORUNFvH0MRJx4mlFk XN6G+5jIIJhG46LUucQ28+VyEDNcGL3tarnkw8ngEhAbnvMJ2RTx8vGh7PssKaGzAUmNNZiG MB4mPKqvDZ02j1wp7vthQcOEg08z1+XHXb8ZZKST7yTVa5P89JymGE8CBGdQaAXnqYK3/yWf FwRDcGV6nxanxZGKEkSHHOm8jHwvQWvPP73pvuPBEPtKGLzbgd7OOcGZWtq2hNC6cRtsRdDx 4TAGMCz4j238m+2mdbdhRh3iBnWT5yPFfnv/2IjFAk+sdix1Mrr+LIDF++kiekeq0yUpDdc4 ExBy2xf6dd+tuFFBp3/VDN4U0UfG4QJ2fg19zE5Z8dS4jGIbLg== In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:KK1pma/5tcyN3UjxqPweoFHXYYro/uASbc93k5BLVCXr9PBZaAk WVImr4NkDkdRbc+Cesq2HDbvI8RdvWVvxJpop4kylhkXo7S5nkmmRiwrqEV1Glm4pDzEEiD U3RM/6V5dWpT6Ebl9D7Qa5q7e0W9SrGTNfxEOoUcskhb6UxGp8eR74lGHJa1T60+M8qOCYS nLZ3IFLRv7AVm3rNUv79g== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:Eb37hDM+tK0=;dnu7EQozlwTxxDIuVS51yug+3SS XpnqsQNjThNPh2gR/nDJgw1edxTDKLvjlW8Hebdyc4SrOR35x6aM6/BbJ0Rn0hUmd5A4j0O+n tMVKWsrNLGQYE5HgUNYgKe1RsHg4p1wvuoyHb85tXgtsxSYRgpzE84V/Gn/0EM6a1W76c8gJz 50v9gqxJX8IWdBFb6kvaSGqzyBnhJG3K9lkS7XSVGf8wSzS9OTJfte2Duv6KkL+fheILaZ2on irxZJQwQlk3bx1grJFPx7VPVzlPKV/33qjqHzjx5eA23IlpKY2t5ZomQlsw1BzbvrpwoPlyPF 2cFS3VP+qXEkv2J1NVgK6cagtrLL4c2NQ3ID0wgmIJPkJFrv/bOqTv7y/U2YYjhRY+YZbA1cu zhJHDodcrvb0AwZQOEq4VUOeMyPcvjrENf++PgX58pcDw7TpjSmKcrSM+0ZIbyyVYZjStErGK m3y9keVNUsvmWpTp5qWkalE+DP/n/b9NBVVgFtZV66Tq/Jo3IfPctH/mYC+runuJ4atFWJYKm vNr5CBIrMaVGEaai8OQq9N5Y3EuSiReBY1lo7NqlpfeN0Hk5dXu2nuTNz3k2BQjKC8NcQXnsw w/LyjB/yEpDYErcphVPJDpZOs3RevAHk4IuEmhCX3kSePPqBcvd0WvhdQmCL1mQFergn+f0DC 2tc9zNImgBwJTP0sk01UsCXNeYayCcIOSIhw1wEArboAk2NLE6KbeizQR6TNQX2zfrho8gmyx HOHX5e/LlQOplGjdZzxsTyPK5cEd/HdTRPG5wPoIobjCyAOh/7yJ7zXGhsZq9Vao4mVpofvps uLxs4VOY1qgOSm4gSL43i9BDYFDp3KmGl1tiYFkcixsmeJYHvsoGdB1rMEjDMVOKw++sm5YwV i/F380wYvrGZjdkCZyi4myoUW62oAcs5LtRu7YVuZdz4wMpACK0yI3HIXC0Ai9VklTR4f9h/e bpMzfibsDiDy++dE5+RnJEyQFxUAaRDt0IlQKUswQSzt09U7b33+/xxRFqkG9Q3bT16MkfRWg MBD8PtN3GhJvwKZt7Wzm0qd+zvHlxGzwM6HikaT2ydBldwXhJyHWSetzR1cwVWzKMNWSAo9gb Ybik9QPDsepQiThdqDbPeHst2aT/vz On 12/11/24 00:53, Helge Deller wrote: > On 12/11/24 00:37, Helge Deller wrote: >> On 12/10/24 16:41, Thomas Zimmermann wrote: >>> Hi >>> >>> >>> Am 10.12.24 um 15:34 schrieb Helge Deller: >>>> On 12/10/24 15:29, Helge Deller wrote: >>>>> On 12/10/24 15:09, Thomas Zimmermann wrote: >>>>>> diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/= Kconfig >>>>>> index 77ab44362f16..577e91ff7bf6 100644 >>>>>> --- a/drivers/staging/fbtft/Kconfig >>>>>> +++ b/drivers/staging/fbtft/Kconfig >>>>>> @@ -3,6 +3,7 @@ menuconfig FB_TFT >>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 tristate "Support for small TFT LCD = display modules" >>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 depends on FB && SPI >>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 depends on FB_DEVICE >>>>>> +=C2=A0=C2=A0=C2=A0 depends on BACKLIGHT_DEVICE_CLASS >>>>> >>>>> Typo. Should be BACKLIGHT_CLASS_DEVICE... >>> >>> Ah, thanks. I'll better check the rest of the series for similar mista= kes. >>> >>>> >>>> Beside the typo: >>>> In this case, doesn't it make sense to "select BACKLIGHT_DEVICE_CLASS= " instead? >>> >>> That causes the dependency error mentioned in the commit message. This= time it's just for fbtft instead of shmobilefb. >>> >>>> If people want the fbtft, backlight support should be enabled too. >>> >>> As a user-visible option, it should not be auto-selected >>> unnecessarily. >> >> Right, it should not be auto-selected. >> Unless if fbtft really needs it enabled to function. >> IMHO all fb/drm drivers have higher priority than some low-level >> background backlight controller code. >> >>> The DRM panel drivers already depend on the backlight >>> instead of selecting it. It's the correct approach. >> >> Sounds wrong IMHO. >> >>> As I mentioned >>> in the cover letter, the few remaining driver that select it should >>> probably be updated. >> >> That dependency sounds weird, but maybe I simply misunderstand your log= ic...? >> >> As a Linux end user I usually know which graphic cards are in my machin= e >> and which ones I want to enable. >> But as a normal user I think I shouldn't be expected to know >> that I first need to enable the "backlight class device" >> so that I'm then able to afterwards enable the fbtft (or any other drm/= fb driver). >> >> Am I wrong? > > Looking closer on this... > You propose: > > --- a/drivers/staging/fbtft/Kconfig > +++ b/drivers/staging/fbtft/Kconfig > @@ -3,6 +3,7 @@ menuconfig FB_TFT > =C2=A0=C2=A0=C2=A0=C2=A0 tristate "Support for small TFT LCD display mo= dules" > =C2=A0=C2=A0=C2=A0=C2=A0 depends on FB && SPI > =C2=A0=C2=A0=C2=A0=C2=A0 depends on FB_DEVICE > +=C2=A0=C2=A0=C2=A0 depends on BACKLIGHT_DEVICE_CLASS > =C2=A0=C2=A0=C2=A0=C2=A0 depends on GPIOLIB || COMPILE_TEST > =C2=A0=C2=A0=C2=A0=C2=A0 select FB_BACKLIGHT > > So, it will depend on BACKLIGHT_DEVICE_CLASS. > But there is "select FB_BACKLIGHT" as well, which is: > config FB_BACKLIGHT > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 tristate > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 depends on FB > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 select BACKLIGHT_CLASS_DEVIC= E > > So, you end up with selecting and depending on BACKLIGHT_CLASS_DEVICE ? Ok. Ignore this ^^^ . I now understand your cover letter. Looking at your DRM tiny drivers and the i915/gma500 DRM drivers, there is a "select BACKLIGHT_CLASS_DEVICE" in those. So, isn't the right approach then something like: =2D-- a/drivers/staging/fbtft/Kconfig tristate "Support for small TFT LCD display modules" depends on FB && SPI depends on FB_DEVICE + select BACKLIGHT_DEVICE_CLASS depends on GPIOLIB || COMPILE_TEST select FB_BACKLIGHT config FB_BACKLIGHT tristate depends on FB + depends on BACKLIGHT_CLASS_DEVICE ?