[PATCH v1] fbtft: fb_st7789v: added reset on init_display()

staging: fbtft: fb_st7789v: reset display before initialization

In rare cases the display is flipped or mirrored. This was observed more
often in a low temperature environment. A clean reset on init_display()
should help to get registers in a sane state.

Signed-off-by: Oliver Graute <redacted>
---
 drivers/staging/fbtft/fb_st7789v.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/fbtft/fb_st7789v.c b/drivers/staging/fbtft/fb_st7789v.c
index 3a280cc1892c..0a2dbed9ffc7 100644
--- a/drivers/staging/fbtft/fb_st7789v.c
+++ b/drivers/staging/fbtft/fb_st7789v.c

@@ -82,6 +82,8 @@ enum st7789v_command {
 {
 	int rc;

+	par->fbtftops.reset(par);
+
 	rc = init_tearing_effect_line(par);
 	if (rc)
 		return rc;

-- 
2.17.1

On Fri, Aug 13, 2021 at 08:25:10AM +0200, Oliver Graute wrote:

staging: fbtft: fb_st7789v: reset display before initialization

What is this line here, and why is this not your subject line instead?

In rare cases the display is flipped or mirrored. This was observed more
often in a low temperature environment. A clean reset on init_display()
should help to get registers in a sane state.

Signed-off-by: Oliver Graute <redacted>

What commit does this fix?

thanks,

greg k-h

On 13/08/21, Greg KH wrote:

On Fri, Aug 13, 2021 at 08:25:10AM +0200, Oliver Graute wrote:

quoted

staging: fbtft: fb_st7789v: reset display before initialization

What is this line here, and why is this not your subject line instead?

I'll put the line as subject instead.

quoted

In rare cases the display is flipped or mirrored. This was observed more
often in a low temperature environment. A clean reset on init_display()
should help to get registers in a sane state.

Signed-off-by: Oliver Graute <redacted>

What commit does this fix?

this is a fix for a rare behavior of the fb_st7789v display. Not a
bugfix for a specific commit.

Best regards,

Oliver

On Fri, Aug 13, 2021 at 02:54:30PM +0200, Oliver Graute wrote:

On 13/08/21, Greg KH wrote:

quoted

On Fri, Aug 13, 2021 at 08:25:10AM +0200, Oliver Graute wrote:

quoted

staging: fbtft: fb_st7789v: reset display before initialization

What is this line here, and why is this not your subject line instead?

I'll put the line as subject instead.

quoted

quoted

In rare cases the display is flipped or mirrored. This was observed more
often in a low temperature environment. A clean reset on init_display()
should help to get registers in a sane state.

Signed-off-by: Oliver Graute <redacted>

What commit does this fix?

this is a fix for a rare behavior of the fb_st7789v display. Not a
bugfix for a specific commit.

So if it has always been broken, list the commit where the code was
added to the kernel, as this should be backported to the stable kernels,
right?

thanks,

greg k-h

On 13/08/21, Greg KH wrote:

On Fri, Aug 13, 2021 at 02:54:30PM +0200, Oliver Graute wrote:

quoted

On 13/08/21, Greg KH wrote:

quoted

On Fri, Aug 13, 2021 at 08:25:10AM +0200, Oliver Graute wrote:

quoted

staging: fbtft: fb_st7789v: reset display before initialization

What is this line here, and why is this not your subject line instead?

I'll put the line as subject instead.

quoted

quoted

In rare cases the display is flipped or mirrored. This was observed more
often in a low temperature environment. A clean reset on init_display()
should help to get registers in a sane state.

Signed-off-by: Oliver Graute <redacted>

What commit does this fix?

this is a fix for a rare behavior of the fb_st7789v display. Not a
bugfix for a specific commit.

So if it has always been broken, list the commit where the code was
added to the kernel, as this should be backported to the stable kernels,
right?

ok thx, will list the commit and add stable@vger.kernel.org to cc

thx,

Oliver