From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anatolij Gustschin Date: Thu, 3 Sep 2015 00:25:55 +0200 Subject: [U-Boot] What's purpose of DEV_FLAGS_SYSTEM and DEV_EXT_VIDEO? In-Reply-To: References: Message-ID: <20150903002555.2780f52b@crub> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Bin, On Mon, 17 Aug 2015 13:09:20 +0800 Bin Meng wrote: ... > I plan to send a patch to remove the DEV_FLAGS_SYSTEM and > DEV_EXT_VIDEO. They look useless to me. For example, > > $ grep -nr DEV_FLAGS_SYSTEM * ... > drivers/video/cfb_console.c:2296: console_dev.flags = > DEV_FLAGS_OUTPUT | DEV_FLAGS_SYSTEM; > drivers/net/netconsole.c:325: dev.flags = DEV_FLAGS_OUTPUT | > DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM; > include/stdio_dev.h:19:#define DEV_FLAGS_SYSTEM 0x80000000 /* > Device is a system device */ > > Except for this one below which tests the flag and prints an 'S', > common/cmd_console.c:33: (dev->flags & > DEV_FLAGS_SYSTEM) ? 'S' : '.', > > I don't see any actual meaning of this flag. I wonder if someone on > the mailing list knows the history. This is very old code, and I do not know the history. Both flags could be dropped, I've no objection. > Also I noticed that several blackfin boards' video driver only set > this flag without setting DEV_FLAGS_OUTPUT. > > board/bf527-ezkit/video.c:442: videodev.flags = DEV_FLAGS_SYSTEM; > /* No Output */ > board/cm-bf548/video.c:336: videodev.flags = DEV_FLAGS_SYSTEM; > /* No Output */ > board/bf548-ezkit/video.c:332: videodev.flags = DEV_FLAGS_SYSTEM; > /* No Output */ > board/bf533-stamp/video.c:168: videodev.flags = DEV_FLAGS_SYSTEM; > > I wonder these video drivers are not used for system output purpose? No, they don't. In the board configs I see that these use very small Displays (320x240). These shows the logo, but it would be very difficult to use such displays as a console. Thanks, Anatolij