From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Fri, 29 Jan 2016 12:20:47 +0000 Subject: Re: [PATCH] video: fbdev: imxfb: Provide a reset mechanism Message-Id: <56AB591F.2030400@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="dlvbbgSO4M4hLXK8P3EpvANq7jvGO2L99" List-Id: References: <1453209057-16444-1-git-send-email-festevam@gmail.com> In-Reply-To: <1453209057-16444-1-git-send-email-festevam@gmail.com> To: linux-fbdev@vger.kernel.org --dlvbbgSO4M4hLXK8P3EpvANq7jvGO2L99 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 19/01/16 15:10, Fabio Estevam wrote: > From: Fabio Estevam >=20 > Currently when we boot the kernel on a mx25pdk the LCDC controller > does not show the Linux logo on boot. >=20 > This problem is well explained by Sascha Hauer: >=20 > "Unfortunately this LCD controller does not have an enable bit. The > controller starts directly when the clocks are enabled. If the clocks > are enabled when the controller is not yet programmed with proper > register values then it just goes into some undefined state. What I > suspect is that the clocks already were enabled before driver probe, > presumably by the bootloader, so the controller is already in undefined= > state when entering Linux. Now by dis/enabling the ipg clock you > effectively reset the controller. Since you have programmed it with > valid register values in the mean time it starts working after this > reset." >=20 > So do as suggested and force a reset of the LCDC hardware by=20 > enabling and disabling the IPG clock. >=20 > With this change the Linux logo can be seen on boot on a mx25pdk. >=20 > Signed-off-by: Fabio Estevam > --- > drivers/video/fbdev/imxfb.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) Thanks. Queued for 4.5 fixes. Tomi --dlvbbgSO4M4hLXK8P3EpvANq7jvGO2L99 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJWq1kfAAoJEPo9qoy8lh714WMP/3irfTUzlSnludBvmmXRPf6I j4BoJhEy5gNbAI5akXWwVzpHVnda3+yGmPeW5FdIwKMzuIGY4X02RQh01TPjUg4/ P/VltCqQMzW7UcLmRGeg/WSrMJMTg7AAqjnUFQ1T79wQ+JVu1bo+PlYJPuP01s1Q RymX/uXqvx6i8fy22p800sMWsHy3c5DnJbKr71VFRA6ukKIMKidLwFQdczQFK47z I3Zd60sOojZ3xe82ZoZP0hwtVKGj9rgmgZMsy4ODEdM6ZCkY0Uh0vsN1Kk9f8aj1 xleMinPeLh31WHHui1j0HAOaOsdh+iMFAaF2TPRidO20xHApOeSL/tkcu/PeBMqN tvOTeV8Y3YwTqL0ZRHeV6L1cUzh59+mr9lTi38YI48YxUxWAeXFYMimgtJVkmllQ 5ir4wTyXDeBVX35r9lOei0nlW76UYsSpLjzr96sdmEqYLzFPtk5ljsTtr8EV4NeZ WjQk4j7/FrUVRPStQUrJ7PWD3bCr3e5o1M2JdbF7+m38Jql1xE5akQyEl6SuYrRe 4h7aHONfc0afIMMvYsTg8v0L04J1lOuEC7q3rw7cdw6BbIr/79Fc1B9q2xAYXubn hjvRPdPiQfhUNiKriTE4a2MJAl1Plh4fPzNchkdsJ9CMWeQjmRpDzDI52+6KUU4A CimNDu09papZkOPN/YWC =sfXC -----END PGP SIGNATURE----- --dlvbbgSO4M4hLXK8P3EpvANq7jvGO2L99--