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authorLars Poeschel <poeschel@lemonage.de>2020-11-03 12:58:26 +0300
committerMiguel Ojeda <ojeda@kernel.org>2020-11-04 13:04:05 +0300
commitaf9470b26dc6c3a8f9ef460c90e34a66ce4f5f1d (patch)
tree2851f82a06b72e90468dddea2c2fbd1b239f3167 /drivers/auxdisplay
parent40c2b72e4b11f0a80dff19b539fccf36472dc417 (diff)
downloadlinux-af9470b26dc6c3a8f9ef460c90e34a66ce4f5f1d.tar.xz
auxdisplay: charlcd: Do not print chars at end of line
Skip printing characters at the end of a display line. This fits to the behaviour we already had, that the cursor is nailed to the last position of a line. This might slightly change behaviour. On hd44780 displays with one or two lines the previous implementation did still write characters to the buffer of the display even if they are currently not visible. The shift_display command could be used to set the "viewing window" to a new position in the buffer and then you could see the characters previously written. This described behaviour does not work for hd44780 displays with more than two display lines. There simply is not enough buffer. So the behaviour was a bit inconsistent across different displays. The new behaviour is to stop writing characters at the end of a visible line, even if there would be room in the buffer. This allows us to have an easy implementation, that should behave equal on all supported displays. This is not hd44780 hardware dependent anymore. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'drivers/auxdisplay')
-rw-r--r--drivers/auxdisplay/charlcd.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index ef10b5ca0e16..f43430e9dcee 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -111,6 +111,9 @@ static void charlcd_home(struct charlcd *lcd)
static void charlcd_print(struct charlcd *lcd, char c)
{
+ if (lcd->addr.x >= lcd->width)
+ return;
+
if (lcd->char_conv)
c = lcd->char_conv[(unsigned char)c];