From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Subject: Re: [PATCH] [#7001] framebuffer: old image of last app would retain for a while after starting new app Date: Fri, 16 Mar 2012 01:21:37 -0400 Message-ID: <201203160121.38650.vapier@gentoo.org> References: <1331628439-12719-1-git-send-email-Aaron.Wu@analog.com> <201203152354.33365.vapier@gentoo.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0257404461028803304==" Return-path: Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1S8Pbh-00058W-VR for linux-fbdev-devel@lists.sourceforge.net; Fri, 16 Mar 2012 05:21:41 +0000 Received: from smtp.gentoo.org ([140.211.166.183]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1S8Pbh-0004pG-11 for linux-fbdev-devel@lists.sourceforge.net; Fri, 16 Mar 2012 05:21:41 +0000 In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: "Zhang, Sonic" Cc: uclinux-dist-devel@blackfin.uclinux.org, "Wu, Aaron" , linux-fbdev-devel@lists.sourceforge.net --===============0257404461028803304== Content-Type: multipart/signed; boundary="nextPart5923779.7REj6ofopc"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart5923779.7REj6ofopc Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On Friday 16 March 2012 01:05:10 Zhang, Sonic wrote: > From: Mike Frysinger [mailto:vapier@gentoo.org] >> On Thursday 15 March 2012 23:34:08 Zhang, Sonic wrote: >>> From: Mike Frysinger [mailto:vapier@gentoo.org] >>>> On Thursday 15 March 2012 05:23:50 Wu, Aaron wrote: >>>>> Old image of last application would retain for a while when >>>>> starting a new application, this patch clear the frambuffer before >>>>> displaying every time the fb is opened. >>>>=20 >>>> i'm not sure the behavior you describe is wrong. in fact, i'm pretty >>>> sure it sounds correct. if an app writes an image to the framebuffer >>>> and then quits, that image should stay there indefinitely until >>>> something else opens the framebuffer and draws their own image. >>>=20 >>> Before the second application draws its own image, the image of last >>> application has already been displayed on the LCD when the second >>> application opens the FB device(PPI is enabled when it is opened). >>> This is not a correct behavior. >>=20 >> sure it is. if the app wants to clear the screen, it can do so. genera= lly >> it's going to anyways by drawing an entire frame. having the frame buff= er >> driver always clear the screen introduces wasted memory overhead as it >> does the memset(), and user-visible jank as the device transitions from = an >> initial splash screen to the main userspace app. >>=20 >> this is a policy decision that doesn't really belong in kernel space. a= nd >> if it did, it should be agreed upon by all frame buffer users and not ju= st >> changing a few drivers. >=20 > How can the application clean the screen before it opens the FB device? why does it need to be before open ? if the kernel does the memset or=20 userspace does the memset, the frame still gets cleared. in looking at the blackfin framebuffer drivers, i'm not sure they're correc= t. i=20 don't think the PPI/DMA should be shutdown when the last user space client= =20 closes it. fb_release is for releasing all resources when tearing down the= =20 driver, and fb_blank is runtime management (turning off vsync/hsync and=20 powering down the screen). =2Dmike --nextPart5923779.7REj6ofopc Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) iQIcBAABAgAGBQJPYs3iAAoJEEFjO5/oN/WBxl4P/iHpnAG3fvuYOHcN4O/XSVlO /6PHottAzRQOgyUCe6+YXxr7hYCT3pkueWd/WiC/nM1aQg+zIvBr2BGNPYlEJPO3 mLG46oldtB24/IvYL7sqR8Emr8IapnMvqHc8tq6FicLdXuu5P6vuob6Ab0yX2Dqh EcPSZ/ShArWM6LIdq3IoUhlulL19uQby/ELdt0W7OAVUHJHzKmbUAMEog6hHi20z KHN+X3Ip2KKmw5i74E48r/yeANR02CviHwb4hQCz7ZHbmhH4t67T69GBp1IeVYgk F/y6yzBUYjOY7eJ+BzSk4swCishJ98MAF4V3bNRUZBr8qZmIm8fQerVMTjmUOZiF JfjZDsu5ueTHoBB1vZdiQEZJ1DtxYTKQAO6murenQlo0UMQknzx/cePQx5LMYfuP 7yNZ2QWVrpSiRQHZOg2mwQPCQeaECD2NLWFhRLNGGmfM22BT3gLpMpRxVFwQH888 FBnwpWHK6BSzMWSJMgp6q4Yb5hTokIJRSoRB3cHqImKrGufLs3R95mNQNFiNz8Mz rkFQ9z2Bf0uHrfT2sgOrhTVEzWI+iGCmu3XRRvpcszZeAhgAgUij8f/sjqUbgGWL 2vs8JoIuwq1f6KS7GhOsLT5mzrLshHA2sSbpHxEj43CNNZ37ebv5qnMyA/osDDbU hecDRR2PxuXSwJNZW3Ax =pNIG -----END PGP SIGNATURE----- --nextPart5923779.7REj6ofopc-- --===============0257404461028803304== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure --===============0257404461028803304== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Linux-fbdev-devel mailing list Linux-fbdev-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel --===============0257404461028803304==--