Re: [PATCH v2 28/32] auxdisplay: hd44780: Remove clear_fast

[Willy Tarreau]

Hi Lars,

On Mon, Sep 21, 2020 at 04:46:40PM +0200, poeschel@xxxxxxxxxxx wrote:
> From: Lars Poeschel <poeschel@xxxxxxxxxxx>
> 
> We remove the hd44780_clear_fast (display) clear implementation. charlcd
> will fall back to use hd44780_common_clear_display then, which is much
> much faster.

I might have got confused, but it looks to me like patches 27 and 28
basically undo patch 26: in 26 you moved code to hd44780 and wrote a
fallback, just to later delete that code.

I seem to remember that the reason for the clear_fast() implementation
is that the default clear_display() is quite slow for small displays,
compared to what can be achieved by just filling the display with spaces
(in the order of tens of milliseconds vs hundreds of microseconds). But
I could be mistaken given how old this is, so please take my comment
with a grain of salt.

Willy