Messages in this thread | | | Subject | Re: [PATCH] backlight: l4f00242t03: Fix reset sequence | From | Alberto Panizzo <> | Date | Wed, 05 Jan 2011 01:32:55 +0100 |
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On Tue, 2011-01-04 at 15:59 -0800, Andrew Morton wrote: > On Sun, 28 Nov 2010 18:13:53 +0100 > Alberto Panizzo <maramaopercheseimorto@gmail.com> wrote: > > > The reset command is part of the init sequence and it take effect > > only if the lcd is powered. > > > > Signed-off-by: Alberto Panizzo <maramaopercheseimorto@gmail.com> > > --- > > > > This patch is built on top of: > > http://userweb.kernel.org/~akpm/mmotm/broken-out/drivers-video-backlight-l4f00242t03c-full-implement-fb-power-states-for-this-lcd.patch > > > > drivers/video/backlight/l4f00242t03.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/video/backlight/l4f00242t03.c b/drivers/video/backlight/l4f00242t03.c > > index 5d25743..c04aa90 100644 > > --- a/drivers/video/backlight/l4f00242t03.c > > +++ b/drivers/video/backlight/l4f00242t03.c > > @@ -62,6 +62,8 @@ static void l4f00242t03_lcd_init(struct spi_device *spi) > > regulator_enable(priv->core_reg); > > } > > > > + l4f00242t03_reset(pdata->reset_gpio); > > + > > gpio_set_value(pdata->data_enable_gpio, 1); > > msleep(60); > > spi_write(spi, (const u8 *)cmd, ARRAY_SIZE(cmd) * sizeof(u16)); > > @@ -225,7 +227,6 @@ static int __devinit l4f00242t03_probe(struct spi_device *spi) > > } > > > > /* Init the LCD */ > > - l4f00242t03_reset(pdata->reset_gpio); > > l4f00242t03_lcd_init(spi); > > priv->lcd_state = FB_BLANK_VSYNC_SUSPEND; > > l4f00242t03_lcd_power_set(priv->ld, FB_BLANK_UNBLANK); > > What were the user-visible effects of the bug which you just fixed? > > Please always include this info when sending a bugfix! Because without > that info it's much harder to work out whether we should backport the > fix into earlier kernels and it's harder for end-users and distro > maintainers to work out if the patch will fix particular behaviour > which they or their customers are seeing. >
The effect of the bug was that the sequence: set lcd power_state to FB_BLANK_POWERDOWN set lcd power_state to FB_BLANK_UNBLANK Did not produced a complete reboot of the LCD which was showing fuzzy colours.
This was not experienced before implementing correctly all the LCD power states with the patch [1]. Since before the patch [1] the regulators were not touched and the LCD shutdown was reached with a register write. After the patch [1] a complete boot sequence with an initial reset is needed for the display every time the LCD is powered up.
drivers-video-backlight-l4f00242t03c-full-implement-fb-power-states-for-this-lcd.patch
Best Regards, -- Alberto!
Be Persistent! - Greg Kroah-Hartman (FOSDEM 2010)
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