Re: Move softcursor out of fbdev to fbcon

["Antonino A. Daplas" <adaplas@gmail.com>]

James Simmons wrote:
>> The changelog says it all. This is a modification of Jon's patch, but
>> I have moved softcursor.c to the console directory.  Also I removed
>> the "select FB_SOFTCURSOR" from video/Kconfig and made the compilation
>> of softcursor unconditional, if framebuffer console is enabled.
>>
>> I don't think the fb_cursor hook is usable by other programs, so we
>> should just restrict this hook for fbcon use only.  For userspace cursor
>> support, we need a new one.  But instead of one function, I believe
>> it's better to provide several.  Ie, something like below:
>>
>> fbcursor_show()         
>> fbcursor_move()
>> fbcursor_loadimage()
>> fbcursor_loadpalette()
>> fbcursor_start()
>> fbcursor_stop() 
>>
>> No need to pass all variables to just, say, move the cursor to x,y.
>>
>> And the next step is to eliminate all fbcon-specific fields from
>> fb_info to another structure, such as fb_imageblit, fb_fillrect,
>> fb_cursor, fb_copyarea.  We'll have a smaller kernel size for
>> if fbcon is not enabled.
>>
>> Comments?
> 
> Its way to big and gross. Please keep it simple!!!!!! 

Actually, it's the other way around. Functions should do just one thing.
In contrast, our fb_cursor() function is doing all of the above
and more.  Breaking up fb_cursor() into several may have a bit of a
memory overhead, but the end result is more efficient code.  Do you really
want the user app to pass the quite large struct fb_cursor to the kernel just
to move the cursor?  Or is it better just to pass two integers, x and y?

Remember, what I'm proposing is an API that is usable by userspace and other
kernel modules, and only if the driver supports a hardware cursor.  The current
fb_cursor() used by fbcon can remain, if that is what you want. Because
fb_cursor() was designed for fbcon (as with all of the fb_* drawing functions),
they can never be used by other modules without a lot of pain.

Tony 




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