On Monday 14 March 2005 22:35, Paul Mundt wrote:

On Mon, Mar 14, 2005 at 10:10:35PM +0800, Antonino A. Daplas wrote:

quoted

BTW, I would guess that scrolling is slow in this driver.  Since this
driver can do pan_display, If this:

info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN;

is added somewhere before register_framebuffer(), and var->xres_virtual >
var->xres, you might get a several-fold increase in scrolling speed
(since scrolling mode will be SCROLL_PAN_REDRAW instead of
SCROLL_REDRAW).

This is interesting. When FBINFO_HWACCEL_YPAN was added to hitfb, it slowed
down scrolling by several orders of magnitude. Perhaps it was something
relating to how the pan_display was implemented, but it's definitely not
a general win for everyone..

Some hardware waits for vblank/vsync before updating the start address, and
in the case of fbcon, that will be for each row of text. So yes, in this
case, ypan is not a win.

Tony




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