From: Willy Tarreau <w@1wt.eu>
To: poeschel@lemonage.de
Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 28/32] auxdisplay: hd44780: Remove clear_fast
Date: Tue, 22 Sep 2020 07:22:27 +0200 [thread overview]
Message-ID: <20200922052227.GA16386@1wt.eu> (raw)
In-Reply-To: <20200921144645.2061313-29-poeschel@lemonage.de>
Hi Lars,
On Mon, Sep 21, 2020 at 04:46:40PM +0200, poeschel@lemonage.de wrote:
> From: Lars Poeschel <poeschel@lemonage.de>
>
> 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
next prev parent reply other threads:[~2020-09-22 5:36 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 8:24 [PATCH 1/3] auxdisplay: Make charlcd.[ch] more general Lars Poeschel
2019-10-16 8:26 ` [PATCH 2/3] auxdisplay: lcd2s DT binding doc Lars Poeschel
2019-10-29 1:24 ` Rob Herring
2019-10-16 8:27 ` [PATCH 3/3] auxdisplay: add a driver for lcd2s character display Lars Poeschel
2019-10-16 16:53 ` [PATCH 1/3] auxdisplay: Make charlcd.[ch] more general Miguel Ojeda
2019-10-17 8:07 ` Lars Poeschel
2019-10-17 11:26 ` Andy Shevchenko
2019-10-18 15:08 ` Miguel Ojeda
2019-10-18 15:33 ` Joe Perches
2019-10-18 21:55 ` Andi Kleen
2020-09-21 14:46 ` [PATCH v2 00/33] Make charlcd device independent poeschel
2020-09-21 14:46 ` [PATCH v2 01/32] auxdisplay: Use an enum for charlcd backlight on/off ops poeschel
2020-09-21 14:46 ` [PATCH v2 02/32] auxdisplay: Introduce hd44780_common.[ch] poeschel
2020-09-21 15:30 ` Randy Dunlap
2020-09-21 14:46 ` [PATCH v2 03/32] auxdisplay: Move hwidth and bwidth to struct hd44780_common poeschel
2020-09-21 14:46 ` [PATCH v2 04/32] auxdisplay: Move ifwidth " poeschel
2020-09-21 14:46 ` [PATCH v2 05/32] auxdisplay: Move write_data pointer to hd44780_common poeschel
2020-09-21 14:46 ` [PATCH v2 06/32] auxdisplay: Move write_cmd pointers to hd44780 drivers poeschel
2020-09-21 14:46 ` [PATCH v2 07/32] auxdisplay: Move addr out of charlcd_priv poeschel
2020-09-21 14:46 ` [PATCH v2 08/32] auxdisplay: hd44780_common_print poeschel
2020-09-22 6:31 ` kernel test robot
2020-09-21 14:46 ` [PATCH v2 09/32] auxdisplay: provide hd44780_common_gotoxy poeschel
2020-09-21 14:46 ` [PATCH v2 10/32] auxdisplay: add home to charlcd_ops poeschel
2020-09-21 14:46 ` [PATCH v2 11/32] auxdisplay: Move clear_display to hd44780_common poeschel
2020-09-21 14:46 ` [PATCH v2 12/32] auxdisplay: make charlcd_backlight visible " poeschel
2020-09-21 14:46 ` [PATCH v2 13/32] auxdisplay: Make use of enum for backlight on / off poeschel
2020-09-21 14:46 ` [PATCH v2 14/32] auxdisplay: Move init_display to hd44780_common poeschel
2020-09-21 14:46 ` [PATCH v2 15/32] auxdisplay: implement hd44780_common_shift_cursor poeschel
2020-09-21 14:46 ` [PATCH v2 16/32] auxdisplay: Implement hd44780_common_display_shift poeschel
2020-09-21 14:46 ` [PATCH v2 17/32] auxdisplay: Implement a hd44780_common_display poeschel
2020-09-21 14:46 ` [PATCH v2 18/32] auxdisplay: Implement hd44780_common_cursor poeschel
2020-09-21 14:46 ` [PATCH v2 19/32] auxdisplay: Implement hd44780_common_blink poeschel
2020-09-21 14:46 ` [PATCH v2 20/32] auxdisplay: cleanup unnecessary hd44780 code in charlcd poeschel
2020-09-21 14:46 ` [PATCH v2 21/32] auxdisplay: Implement hd44780_common_fontsize poeschel
2020-09-21 14:46 ` [PATCH v2 22/32] auxdisplay: Implement hd44780_common_lines poeschel
2020-09-21 14:46 ` [PATCH v2 23/32] auxdisplay: Remove unnecessary hd44780 from charlcd poeschel
2020-09-21 14:46 ` [PATCH v2 24/32] auxdisplay: Move char redefine code to hd44780_common poeschel
2020-09-21 14:46 ` [PATCH v2 25/32] auxdisplay: Call charlcd_backlight in place poeschel
2020-09-21 14:46 ` [PATCH v2 26/32] auxdisplay: Move clear_fast to hd44780 poeschel
2020-09-21 14:46 ` [PATCH v2 27/32] auxdisplay: remove naive display clear impl poeschel
2020-09-21 14:46 ` [PATCH v2 28/32] auxdisplay: hd44780: Remove clear_fast poeschel
2020-09-22 5:22 ` Willy Tarreau [this message]
2020-09-22 8:49 ` Lars Poeschel
2020-09-22 9:21 ` Willy Tarreau
2020-09-22 11:51 ` Lars Poeschel
2020-09-21 14:46 ` [PATCH v2 29/32] auxdisplay: charlcd: replace last device specific stuff poeschel
2020-09-21 14:46 ` [PATCH v2 30/32] auxdisplay: Change gotoxy calling interface poeschel
2020-09-21 14:46 ` [PATCH v2 31/32] auxdisplay: charlcd: Do not print chars at end of line poeschel
2020-09-22 5:27 ` Willy Tarreau
2020-09-22 9:44 ` Lars Poeschel
2020-09-22 10:04 ` Willy Tarreau
2020-09-22 10:20 ` Miguel Ojeda
2020-09-22 11:51 ` Lars Poeschel
2020-09-21 14:46 ` [PATCH v2 32/32] auxdisplay: lcd2s DT binding doc poeschel
2020-09-22 15:58 ` Rob Herring
2020-10-02 13:45 ` Lars Poeschel
2020-09-21 14:46 ` [PATCH v2 33/33] auxdisplay: add a driver for lcd2s character display poeschel
2020-09-21 15:33 ` Randy Dunlap
2020-10-02 12:42 ` Pavel Machek
2020-10-02 13:15 ` Lars Poeschel
2020-09-22 5:31 ` [PATCH v2 00/33] Make charlcd device independent Willy Tarreau
2020-09-22 10:23 ` Miguel Ojeda
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