| Message ID | 1453771756-5418-1-git-send-email-stefan@agner.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Shawn, On 2016-01-25 17:29, Stefan Agner wrote: > The PIXDATA flags of the display_flags enum are controller centric, > e.g. NEGEDGE means the controller shall drive the data signals on > pixelclocks negative edge. However, the drivers flag is display > centric: Sample the data on negative (falling) edge. > > Therefore, change the if statement to check for the POSEDGE flag > (which is typically not set): > Drive on positive edge => sample on negative edge Any comment on that patch? -- Stefan > > Signed-off-by: Stefan Agner <stefan@agner.ch> > --- > Hi all > > Shawn, I would like to have at least your Ack on this before merge. > > It seems that this has been wrong since the driver is able to use > the timings from the device tree, introduced with 669406534b4a > ("video: mxsfb: get display timings from device tree"). > > Not sure how many device trees actually specify the wrong pixel clock > polarity due to that. At least the initial flag convertion from the > old platform data structures done with 0d9f8217db15 ("ARM: mxs: move > display timing configurations into device tree") seems to be affected > and would need to be changed accordingly... > > Not sure how we should handle this, maybe just invert all > pixelclk-active properties where the mxsfb driver is in use...? > > -- > Stefan > > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c > index 4e6608c..38898a9 100644 > --- a/drivers/video/fbdev/mxsfb.c > +++ b/drivers/video/fbdev/mxsfb.c > @@ -150,7 +150,7 @@ > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 > bit width */ > > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ > > enum mxsfb_devtype { > MXSFB_V3, > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, > > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) > + > + /* > + * The PIXDATA flags of the display_flags enum are controller > + * centric, e.g. NEGEDGE means drive data on negative edge. > + * However, the drivers flag is display centric: Sample the > + * data on negative (falling) edge. Therefore, check for the > + * POSEDGE flag: > + * drive on positive edge => sample on negative edge > + */ > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; > > put_display_node: -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi all, what is the state of this patch? Two days ago I had trouble running a TFT panel properly on a iMX6 board because of problem that this patch aims to solve. I saw that an affine patch from same author was accepted into drm/fbdev (commit 53990e416bb7adaa59d045f325a47f31a11b75ee "drm: mxsfb: fix pixel clock polarity" on mainline branch). Thanks in advance, regards Mauro > Hi Shawn, > > On 2016-01-25 17:29, Stefan Agner wrote: > > The PIXDATA flags of the display_flags enum are controller centric, > > e.g. NEGEDGE means the controller shall drive the data signals on > > pixelclocks negative edge. However, the drivers flag is display > > centric: Sample the data on negative (falling) edge. > > > > Therefore, change the if statement to check for the POSEDGE flag > > (which is typically not set): > > Drive on positive edge => sample on negative edge > > Any comment on that patch? > > -- > Stefan > > > > > > Signed-off-by: Stefan Agner <stefan@agner.ch> > > --- > > Hi all > > > > Shawn, I would like to have at least your Ack on this before merge. > > > > It seems that this has been wrong since the driver is able to use > > the timings from the device tree, introduced with 669406534b4a > > ("video: mxsfb: get display timings from device tree"). > > > > Not sure how many device trees actually specify the wrong pixel > clock > > polarity due to that. At least the initial flag convertion from the > > old platform data structures done with 0d9f8217db15 ("ARM: mxs: > move > > display timing configurations into device tree") seems to be > affected > > and would need to be changed accordingly... > > > > Not sure how we should handle this, maybe just invert all > > pixelclk-active properties where the mxsfb driver is in use...? > > > > -- > > Stefan > > > > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/video/fbdev/mxsfb.c > b/drivers/video/fbdev/mxsfb.c > > index 4e6608c..38898a9 100644 > > --- a/drivers/video/fbdev/mxsfb.c > > +++ b/drivers/video/fbdev/mxsfb.c > > @@ -150,7 +150,7 @@ > > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of > 24 > > bit width */ > > > > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) > > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive > edge sampling */ > > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative > edge sampling */ > > > > enum mxsfb_devtype { > > MXSFB_V3, > > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct > mxsfb_info *host, > > > > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) > > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; > > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) > > + > > + /* > > + * The PIXDATA flags of the display_flags enum are > controller > > + * centric, e.g. NEGEDGE means drive data on negative > edge. > > + * However, the drivers flag is display centric: Sample > the > > + * data on negative (falling) edge. Therefore, check for > the > > + * POSEDGE flag: > > + * drive on positive edge => sample on negative edge > > + */ > > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) > > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; > > > > put_display_node: > -- > To unsubscribe from this list: send the line "unsubscribe linux- > fbdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html On 2016-01-25 17:29, Stefan Agner wrote: > The PIXDATA flags of the display_flags enum are controller centric, > e.g. NEGEDGE means the controller shall drive the data signals on > pixelclocks negative edge. However, the drivers flag is display > centric: Sample the data on negative (falling) edge. > > Therefore, change the if statement to check for the POSEDGE flag > (which is typically not set): > Drive on positive edge => sample on negative edge Any comment on that patch? -- Stefan > > Signed-off-by: Stefan Agner <stefan@agner.ch> > --- > Hi all > > Shawn, I would like to have at least your Ack on this before merge. > > It seems that this has been wrong since the driver is able to use > the timings from the device tree, introduced with 669406534b4a > ("video: mxsfb: get display timings from device tree"). > > Not sure how many device trees actually specify the wrong pixel clock > polarity due to that. At least the initial flag convertion from the > old platform data structures done with 0d9f8217db15 ("ARM: mxs: move > display timing configurations into device tree") seems to be affected > and would need to be changed accordingly... > > Not sure how we should handle this, maybe just invert all > pixelclk-active properties where the mxsfb driver is in use...? > > -- > Stefan > > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c > index 4e6608c..38898a9 100644 > --- a/drivers/video/fbdev/mxsfb.c > +++ b/drivers/video/fbdev/mxsfb.c > @@ -150,7 +150,7 @@ > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 > bit width */ > > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ > > enum mxsfb_devtype { > MXSFB_V3, > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, > > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) > + > + /* > + * The PIXDATA flags of the display_flags enum are controller > + * centric, e.g. NEGEDGE means drive data on negative edge. > + * However, the drivers flag is display centric: Sample the > + * data on negative (falling) edge. Therefore, check for the > + * POSEDGE flag: > + * drive on positive edge => sample on negative edge > + */ > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; > > put_display_node: -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, Stefan/Shawn: Should I merge this patch? It seems to be still needed: https://www.spinics.net/lists/linux-fbdev/msg23112.html Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics On Friday, May 06, 2016 01:29:59 PM Stefan Agner wrote: > Hi Shawn, > > On 2016-01-25 17:29, Stefan Agner wrote: > > The PIXDATA flags of the display_flags enum are controller centric, > > e.g. NEGEDGE means the controller shall drive the data signals on > > pixelclocks negative edge. However, the drivers flag is display > > centric: Sample the data on negative (falling) edge. > > > > Therefore, change the if statement to check for the POSEDGE flag > > (which is typically not set): > > Drive on positive edge => sample on negative edge > > Any comment on that patch? > > -- > Stefan > > > > > > Signed-off-by: Stefan Agner <stefan@agner.ch> > > --- > > Hi all > > > > Shawn, I would like to have at least your Ack on this before merge. > > > > It seems that this has been wrong since the driver is able to use > > the timings from the device tree, introduced with 669406534b4a > > ("video: mxsfb: get display timings from device tree"). > > > > Not sure how many device trees actually specify the wrong pixel clock > > polarity due to that. At least the initial flag convertion from the > > old platform data structures done with 0d9f8217db15 ("ARM: mxs: move > > display timing configurations into device tree") seems to be affected > > and would need to be changed accordingly... > > > > Not sure how we should handle this, maybe just invert all > > pixelclk-active properties where the mxsfb driver is in use...? > > > > -- > > Stefan > > > > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c > > index 4e6608c..38898a9 100644 > > --- a/drivers/video/fbdev/mxsfb.c > > +++ b/drivers/video/fbdev/mxsfb.c > > @@ -150,7 +150,7 @@ > > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 > > bit width */ > > > > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) > > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ > > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ > > > > enum mxsfb_devtype { > > MXSFB_V3, > > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, > > > > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) > > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; > > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) > > + > > + /* > > + * The PIXDATA flags of the display_flags enum are controller > > + * centric, e.g. NEGEDGE means drive data on negative edge. > > + * However, the drivers flag is display centric: Sample the > > + * data on negative (falling) edge. Therefore, check for the > > + * POSEDGE flag: > > + * drive on positive edge => sample on negative edge > > + */ > > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) > > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; > > > > put_display_node: -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2017-10-17 15:56, Bartlomiej Zolnierkiewicz wrote: > Hi, > > Stefan/Shawn: > > Should I merge this patch? It seems to be still needed: > > https://www.spinics.net/lists/linux-fbdev/msg23112.html In my opinion yes, it fixes an issue... FWIW, I normally use the DRM driver when using mainline which does not suffer from this issue, so I did not mind much that this fix never made it... -- Stefan > > Best regards, > -- > Bartlomiej Zolnierkiewicz > Samsung R&D Institute Poland > Samsung Electronics > > On Friday, May 06, 2016 01:29:59 PM Stefan Agner wrote: >> Hi Shawn, >> >> On 2016-01-25 17:29, Stefan Agner wrote: >> > The PIXDATA flags of the display_flags enum are controller centric, >> > e.g. NEGEDGE means the controller shall drive the data signals on >> > pixelclocks negative edge. However, the drivers flag is display >> > centric: Sample the data on negative (falling) edge. >> > >> > Therefore, change the if statement to check for the POSEDGE flag >> > (which is typically not set): >> > Drive on positive edge => sample on negative edge >> >> Any comment on that patch? >> >> -- >> Stefan >> >> >> > >> > Signed-off-by: Stefan Agner <stefan@agner.ch> >> > --- >> > Hi all >> > >> > Shawn, I would like to have at least your Ack on this before merge. >> > >> > It seems that this has been wrong since the driver is able to use >> > the timings from the device tree, introduced with 669406534b4a >> > ("video: mxsfb: get display timings from device tree"). >> > >> > Not sure how many device trees actually specify the wrong pixel clock >> > polarity due to that. At least the initial flag convertion from the >> > old platform data structures done with 0d9f8217db15 ("ARM: mxs: move >> > display timing configurations into device tree") seems to be affected >> > and would need to be changed accordingly... >> > >> > Not sure how we should handle this, maybe just invert all >> > pixelclk-active properties where the mxsfb driver is in use...? >> > >> > -- >> > Stefan >> > >> > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- >> > 1 file changed, 11 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c >> > index 4e6608c..38898a9 100644 >> > --- a/drivers/video/fbdev/mxsfb.c >> > +++ b/drivers/video/fbdev/mxsfb.c >> > @@ -150,7 +150,7 @@ >> > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 >> > bit width */ >> > >> > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) >> > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ >> > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ >> > >> > enum mxsfb_devtype { >> > MXSFB_V3, >> > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, >> > >> > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) >> > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; >> > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) >> > + >> > + /* >> > + * The PIXDATA flags of the display_flags enum are controller >> > + * centric, e.g. NEGEDGE means drive data on negative edge. >> > + * However, the drivers flag is display centric: Sample the >> > + * data on negative (falling) edge. Therefore, check for the >> > + * POSEDGE flag: >> > + * drive on positive edge => sample on negative edge >> > + */ >> > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) >> > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; >> > >> > put_display_node: -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Oct 17, 2017 at 03:56:19PM +0200, Bartlomiej Zolnierkiewicz wrote: > > Hi, > > Stefan/Shawn: > > Should I merge this patch? It seems to be still needed: Acked-by: Shawn Guo <shawnguo@kernel.org> -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, October 17, 2017 06:01:58 PM Stefan Agner wrote: > On 2017-10-17 15:56, Bartlomiej Zolnierkiewicz wrote: > > Hi, > > > > Stefan/Shawn: > > > > Should I merge this patch? It seems to be still needed: > > > > https://www.spinics.net/lists/linux-fbdev/msg23112.html > > In my opinion yes, it fixes an issue... > > FWIW, I normally use the DRM driver when using mainline which does not > suffer from this issue, so I did not mind much that this fix never made > it... I queued your patch (with Shawn's ACK) for 4.15, thanks! Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics > -- > Stefan > > > > > Best regards, > > -- > > Bartlomiej Zolnierkiewicz > > Samsung R&D Institute Poland > > Samsung Electronics > > > > On Friday, May 06, 2016 01:29:59 PM Stefan Agner wrote: > >> Hi Shawn, > >> > >> On 2016-01-25 17:29, Stefan Agner wrote: > >> > The PIXDATA flags of the display_flags enum are controller centric, > >> > e.g. NEGEDGE means the controller shall drive the data signals on > >> > pixelclocks negative edge. However, the drivers flag is display > >> > centric: Sample the data on negative (falling) edge. > >> > > >> > Therefore, change the if statement to check for the POSEDGE flag > >> > (which is typically not set): > >> > Drive on positive edge => sample on negative edge > >> > >> Any comment on that patch? > >> > >> -- > >> Stefan > >> > >> > >> > > >> > Signed-off-by: Stefan Agner <stefan@agner.ch> > >> > --- > >> > Hi all > >> > > >> > Shawn, I would like to have at least your Ack on this before merge. > >> > > >> > It seems that this has been wrong since the driver is able to use > >> > the timings from the device tree, introduced with 669406534b4a > >> > ("video: mxsfb: get display timings from device tree"). > >> > > >> > Not sure how many device trees actually specify the wrong pixel clock > >> > polarity due to that. At least the initial flag convertion from the > >> > old platform data structures done with 0d9f8217db15 ("ARM: mxs: move > >> > display timing configurations into device tree") seems to be affected > >> > and would need to be changed accordingly... > >> > > >> > Not sure how we should handle this, maybe just invert all > >> > pixelclk-active properties where the mxsfb driver is in use...? > >> > > >> > -- > >> > Stefan > >> > > >> > drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- > >> > 1 file changed, 11 insertions(+), 2 deletions(-) > >> > > >> > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c > >> > index 4e6608c..38898a9 100644 > >> > --- a/drivers/video/fbdev/mxsfb.c > >> > +++ b/drivers/video/fbdev/mxsfb.c > >> > @@ -150,7 +150,7 @@ > >> > #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 > >> > bit width */ > >> > > >> > #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) > >> > -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ > >> > +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ > >> > > >> > enum mxsfb_devtype { > >> > MXSFB_V3, > >> > @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, > >> > > >> > if (vm.flags & DISPLAY_FLAGS_DE_HIGH) > >> > host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; > >> > - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) > >> > + > >> > + /* > >> > + * The PIXDATA flags of the display_flags enum are controller > >> > + * centric, e.g. NEGEDGE means drive data on negative edge. > >> > + * However, the drivers flag is display centric: Sample the > >> > + * data on negative (falling) edge. Therefore, check for the > >> > + * POSEDGE flag: > >> > + * drive on positive edge => sample on negative edge > >> > + */ > >> > + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) > >> > host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; > >> > > >> > put_display_node: -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c index 4e6608c..38898a9 100644 --- a/drivers/video/fbdev/mxsfb.c +++ b/drivers/video/fbdev/mxsfb.c @@ -150,7 +150,7 @@ #define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 bit width */ #define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6) -#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */ +#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */ enum mxsfb_devtype { MXSFB_V3, @@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, if (vm.flags & DISPLAY_FLAGS_DE_HIGH) host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT; - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) + + /* + * The PIXDATA flags of the display_flags enum are controller + * centric, e.g. NEGEDGE means drive data on negative edge. + * However, the drivers flag is display centric: Sample the + * data on negative (falling) edge. Therefore, check for the + * POSEDGE flag: + * drive on positive edge => sample on negative edge + */ + if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE) host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT; put_display_node:
The PIXDATA flags of the display_flags enum are controller centric, e.g. NEGEDGE means the controller shall drive the data signals on pixelclocks negative edge. However, the drivers flag is display centric: Sample the data on negative (falling) edge. Therefore, change the if statement to check for the POSEDGE flag (which is typically not set): Drive on positive edge => sample on negative edge Signed-off-by: Stefan Agner <stefan@agner.ch> --- Hi all Shawn, I would like to have at least your Ack on this before merge. It seems that this has been wrong since the driver is able to use the timings from the device tree, introduced with 669406534b4a ("video: mxsfb: get display timings from device tree"). Not sure how many device trees actually specify the wrong pixel clock polarity due to that. At least the initial flag convertion from the old platform data structures done with 0d9f8217db15 ("ARM: mxs: move display timing configurations into device tree") seems to be affected and would need to be changed accordingly... Not sure how we should handle this, maybe just invert all pixelclk-active properties where the mxsfb driver is in use...? -- Stefan drivers/video/fbdev/mxsfb.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)