On 12/02/14 19:54, Tomi Valkeinen wrote: > On 11/02/14 21:07, Ryan Mallon wrote: >> On 12/02/14 03:06, Tomi Valkeinen wrote: >> >>> On 20/09/13 10:06, Ryan Mallon wrote: >>>> Several video drivers open code the fb_write write function with code >>>> which is very similar to fb_sys_write. Replace the open code versions >>>> with calls to fb_sys_write. An fb_sync callback is added to each of >>>> the drivers. >>>> >>>> Signed-off-by: Ryan Mallon <rmallon@xxxxxxxxx> >>>> --- >>> >>> Doesn't this change the behavior so that fb_write does no longer update >>> the display, but fb_sync does? I don't think fb_sync is even meant to >>> update the display, it's meant to wait for an update to finish. Then >>> again, I'm not sure about that, all I see in fb.h is "wait for blit >>> idle, optional" >> >> >> fb_write() in fbmem.c calls ->fb_sync() after ->fb_write(), and I've set >> the fb_sync() for each of the drivers, so the behaviour should be >> unchanged for writes. >> >> The fb_sync() function is also called by fb_read() and >> fb_get_buffer_offset() (if FB_PIXMAP_SYNC flag is set). I don't know if >> that will adversely affect behaviour. > > Well, by just looking at the function names the drivers' fb_syncs call, > it sounds to me that with your patch fb_sync will update the LCD, i.e. > send data to it. Doing that in fb_read sounds totally wrong. Well, the alternative is to supply an fb_write() implementation for each driver that calls fb_sys_write(), and then updates the display. The fb_sync() additions can be removed. That would cut down the boiler-plate code, and should keep the behaviour the same. If you don't think it is worth the effort, then the patch can just be dropped. ~Ryan -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
