From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Fri, 12 Feb 2016 07:42:41 +0000 Subject: Re: [PATCH] video: fbdev: imxfb: Provide a reset mechanism Message-Id: <56BD8CF1.3060003@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="xxoh6UFcJ1AkNsWwnu5QHSvo7xcOS63nU" 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 --xxoh6UFcJ1AkNsWwnu5QHSvo7xcOS63nU Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 10/02/16 21:52, Fabio Estevam wrote: > Hi Tomi, >=20 > On Fri, Jan 29, 2016 at 10:20 AM, Tomi Valkeinen wrote: >> >> >> On 19/01/16 15:10, Fabio Estevam wrote: >>> From: Fabio Estevam >>> >>> Currently when we boot the kernel on a mx25pdk the LCDC controller >>> does not show the Linux logo on boot. >>> >>> This problem is well explained by Sascha Hauer: >>> >>> "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 undefin= ed >>> 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." >>> >>> So do as suggested and force a reset of the LCDC hardware by >>> enabling and disabling the IPG clock. >>> >>> With this change the Linux logo can be seen on boot on a mx25pdk. >>> >>> Signed-off-by: Fabio Estevam >>> --- >>> drivers/video/fbdev/imxfb.c | 15 +++++++++++++++ >>> 1 file changed, 15 insertions(+) >> >> Thanks. Queued for 4.5 fixes. >=20 > Still don't see this one applied in Linus nor linux-next tree yet. I've been a bit preoccupied, but I hope I get to send the pull request today. Tomi --xxoh6UFcJ1AkNsWwnu5QHSvo7xcOS63nU 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 iQIcBAEBCAAGBQJWvYzxAAoJEPo9qoy8lh71Rv0P/22iRnJvfimOvSjC0NgVaw2R AB/GMS51BiHZQ2/7XRMWYXAUWEj+GQsNntQOiUOoGH9PURbJuwpwI3z5LWshEcwI d8p6WXAsczOgYHiE6HGCbnEzICFpbvEgrmd1qe5fL5ya814sm9BEEupfP8zP7mLb RYxzjdvC88kFRHneov1uqEzN6zjyTDhG1RLC5iebLUS/dEZSLTBUDvUujxgiZwYF sTXEnnRhXJmp3ur+/luw5tWECGWEwkfAVEJQ+kaiiSJQHbhBlykT/MDCaCtq7IYS mkAWb72aE6kOyTqSjHTgTy6BclfauLrBIc6Wy/S8r1IZMKD2Rssp20oMUI8Re5J0 vC4s0utznSgr/snFEeU8caOL6opnYFJRFZxyXTxtaxag0ug0RI3c/WsDcW2AadhD VZOnJCjCCwCLXJij9otFkUjaagP3J+Lf5StHul3ICFphkUSOOOrS1iikdNV5TSA3 By3kN+6mw4IIlwPFpu9VA+3crq+SXB7ux1FREqIyIqTZxTkMpkS3RtZcG8J5PhXz qMKOuCa4da10paf+IAEtUw/hUN0K6DdQ3Dh8t+FNxOdk4rfDIRylkSqBRs3tTkcN K5KBWpCTFe8p9BMwkxqxhETUF88tsvRxrfymeM0Nlq9glgFCwj7VHYyUkLP+gNHZ Rp4egRGx/9AiW1cvJZbh =Bbp1 -----END PGP SIGNATURE----- --xxoh6UFcJ1AkNsWwnu5QHSvo7xcOS63nU--