| Message ID | 20231116180743.2763021-2-javierm@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Thu, Nov 16, 2023 at 07:07:38PM +0100, Javier Martinez Canillas wrote: > This is used to specify the page start address offset of the display RAM. > > The value is used as offset when setting the page start address with the > SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to > 1 if the property is not present in the Device Tree. > > But the datasheet mentions that the value on reset for the page start is a > 0, so it makes more sense to also have 0 as the default value for the page > offset if the property is not present. > > In fact, using a default value of 1 leads to the display not working when > the fbdev is attached to the framebuffer console. > > Reported-by: Sahaj Sarup <sahaj.sarup@linaro.org> Closes? Fixes? > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Andy Shevchenko <andriy.shevchenko@linux.intel.com> writes: Hello Andy, > On Thu, Nov 16, 2023 at 07:07:38PM +0100, Javier Martinez Canillas wrote: >> This is used to specify the page start address offset of the display RAM. >> >> The value is used as offset when setting the page start address with the >> SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to >> 1 if the property is not present in the Device Tree. >> >> But the datasheet mentions that the value on reset for the page start is a >> 0, so it makes more sense to also have 0 as the default value for the page >> offset if the property is not present. >> >> In fact, using a default value of 1 leads to the display not working when >> the fbdev is attached to the framebuffer console. >> >> Reported-by: Sahaj Sarup <sahaj.sarup@linaro.org> > > Closes? There's no report in a mailing list or bug tracker to reference. > Fixes? > Since the default has been the same since the driver was merged, it doesn't make that much sense for me to reference that commit.
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 5ae48e36fccb..34f014bf4994 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -637,7 +637,7 @@ static int ssd1307fb_probe(struct i2c_client *client) par->height = 16; if (device_property_read_u32(dev, "solomon,page-offset", &par->page_offset)) - par->page_offset = 1; + par->page_offset = 0; if (device_property_read_u32(dev, "solomon,col-offset", &par->col_offset)) par->col_offset = 0;
This is used to specify the page start address offset of the display RAM. The value is used as offset when setting the page start address with the SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to 1 if the property is not present in the Device Tree. But the datasheet mentions that the value on reset for the page start is a 0, so it makes more sense to also have 0 as the default value for the page offset if the property is not present. In fact, using a default value of 1 leads to the display not working when the fbdev is attached to the framebuffer console. Reported-by: Sahaj Sarup <sahaj.sarup@linaro.org> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> --- drivers/video/fbdev/ssd1307fb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)