[U-Boot] What's purpose of DEV_FLAGS_SYSTEM and DEV_EXT_VIDEO?
Simon Glass
sjg at chromium.org
Wed Sep 2 16:05:47 CEST 2015
Hi,
On 2 September 2015 at 03:44, Bin Meng <bmeng.cn at gmail.com> wrote:
> On Mon, Aug 17, 2015 at 1:09 PM, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi,
>>
>> 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 *
>> arch/blackfin/cpu/jtag-console.c:186: dev.flags = DEV_FLAGS_OUTPUT |
>> DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
>> board/bf527-ezkit/video.c:442: videodev.flags = DEV_FLAGS_SYSTEM;
>> /* No Output */
>> board/kosagi/novena/novena.c:80: .flags =
>> DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM,
>> board/cm-bf548/video.c:336: videodev.flags = DEV_FLAGS_SYSTEM;
>> /* No Output */
>> board/mpl/common/kbd.c:206: kbddev.flags = DEV_FLAGS_INPUT |
>> DEV_FLAGS_SYSTEM;
>> board/mpl/pati/pati.c:569: pci_con_dev.flags = DEV_FLAGS_OUTPUT |
>> DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
>> board/bf548-ezkit/video.c:332: videodev.flags = DEV_FLAGS_SYSTEM;
>> /* No Output */
>> board/bf533-stamp/video.c:168: videodev.flags = DEV_FLAGS_SYSTEM;
>> common/cmd_console.c:33: (dev->flags &
>> DEV_FLAGS_SYSTEM) ? 'S' : '.',
>> common/usb_kbd.c:505: usb_kbd_dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
>> common/stdio.c:91: dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT
>> | DEV_FLAGS_SYSTEM;
>> common/stdio.c:102: dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT
>> | DEV_FLAGS_SYSTEM;
>> drivers/input/cros_ec_keyb.c:261: dev.flags = DEV_FLAGS_INPUT |
>> DEV_FLAGS_SYSTEM;
>> drivers/input/tegra-kbc.c:361: dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
>> drivers/input/keyboard.c:277: kbddev.flags = DEV_FLAGS_INPUT |
>> 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.
>>
>> 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?
>>
>
> Ping?
This is from the dawn of time and I don't see any purpose still remaining.
Regards,
Simon
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