Nouveau - Aug 2015 - [PATCH 0/2] drm/nouveau: add support for 2560x1440@56 over HDMI

These patches are adding support for outputting 2560x1440 at 56 over HDMI. 
This needs a pixel clock of 225 MHz which was not supported before.

This was tested in a dual monitor setup with a GF114 (GTX 560 TI) and 
one HDMI monitor running with 2560x1440 at 56 and one DVI monitor running 
with 1920x1200 at 60. This still needs testing on other graphics cards and 
with dual link DVI.

There is no Maintainers entry for nouveau.

Hauke Mehrtens (2):
  drm/nouveau: activate dual link TMDS links only when possible
  drm/nouveau: increase max pixel clock to 225 MHZ for HDMI

 drivers/gpu/drm/nouveau/nouveau_connector.c      | 6 ++++--
 drivers/gpu/drm/nouveau/nv50_display.c           | 8 ++++----
 drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c | 2 +-
 drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c  | 2 +-
 4 files changed, 10 insertions(+), 8 deletions(-)

-- 
2.1.4

Without this patch a pixel clock rate above 165 MHz on a TMDS link is
assumed to be dual link. This is true for DVI, but not for HDMI. HDMI
supports no dual link, but it supports pixel clock rates above 165 MHz.
Only activate Dual Link mode when it is actual possible.

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 drivers/gpu/drm/nouveau/nv50_display.c           | 8 ++++----
 drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c | 2 +-
 drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c  | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nv50_display.c
b/drivers/gpu/drm/nouveau/nv50_display.c
index 981342d..7d11763 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1936,10 +1936,10 @@ nv50_sor_mode_set(struct drm_encoder *encoder, struct
drm_display_mode *umode,
 	switch (nv_encoder->dcb->type) {
 	case DCB_OUTPUT_TMDS:
 		if (nv_encoder->dcb->sorconf.link & 1) {
-			if (mode->clock < 165000)
-				proto = 0x1;
-			else
-				proto = 0x5;
+			proto = 0x1;
+			if (mode->clock >= 165000 &&
+			    nv_encoder->dcb->duallink_possible)
+				proto |= 0x4;
 		} else {
 			proto = 0x2;
 		}
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c
b/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c
index 7f2f05f..ed2b08f 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c
@@ -895,7 +895,7 @@ exec_clkcmp(struct nv50_disp_priv *priv, int head, int id,
u32 pclk, u32 *conf)
 	switch (outp->info.type) {
 	case DCB_OUTPUT_TMDS:
 		*conf = (ctrl & 0x00000f00) >> 8;
-		if (pclk >= 165000)
+		if (pclk >= 165000 && outp->info.duallink_possible)
 			*conf |= 0x0100;
 		break;
 	case DCB_OUTPUT_LVDS:
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
b/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
index 8ba808d..594c228 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
@@ -1544,7 +1544,7 @@ exec_clkcmp(struct nv50_disp_priv *priv, int head, int id,
u32 pclk, u32 *conf)
 		switch (outp->info.type) {
 		case DCB_OUTPUT_TMDS:
 			*conf = (ctrl & 0x00000f00) >> 8;
-			if (pclk >= 165000)
+			if (pclk >= 165000 && outp->info.duallink_possible)
 				*conf |= 0x0100;
 			break;
 		case DCB_OUTPUT_LVDS:
-- 
2.1.4

The Nvidia blob allows a pixel clock up to 225 MHz in version 346.59,
but only allowed 165MHz in version 295 for HDMI connections. This was
tested with a GF114 (Nvidia GTX 560 TI) and a HDMI monitor which used
225 MHz pixel clock and a signal link DVI monitor with a pixel clock of
less than 165 MHz. This should also be tested with some other device,
but I only have this one graphics card.

The HDMI standard <= 1.2 allowed a maximal pixel clock of 165 MHz and
the HDMI standard >= 1.3 allows a maximal pixel clock of 340 MHz. One
DVI link only allows a maximum clock of 165 MHz, so this should only be
changed for HDMI.

My assumption is that all Nvidia cards with HDMI support a Pixel clock
of 225 MHz, but I haven't tested this

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 drivers/gpu/drm/nouveau/nouveau_connector.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c
b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 3162040..9191545b 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -815,8 +815,10 @@ get_tmds_link_bandwidth(struct drm_connector *connector)
 	struct nouveau_drm *drm = nouveau_drm(connector->dev);
 	struct dcb_output *dcb = nv_connector->detected_encoder->dcb;
 
-	if (dcb->location != DCB_LOC_ON_CHIP ||
-	    drm->device.info.chipset >= 0x46)
+	if (drm_detect_hdmi_monitor(nv_connector->edid))
+		return 225000;
+	else if (dcb->location != DCB_LOC_ON_CHIP ||
+		 drm->device.info.chipset >= 0x46)
 		return 165000;
 	else if (drm->device.info.chipset >= 0x40)
 		return 155000;
-- 
2.1.4

On 08/08/2015 07:01 PM, Hauke Mehrtens wrote:
> These patches are adding support for outputting 2560x1440 at 56 over HDMI. 
> This needs a pixel clock of 225 MHz which was not supported before.
> 
> This was tested in a dual monitor setup with a GF114 (GTX 560 TI) and 
> one HDMI monitor running with 2560x1440 at 56 and one DVI monitor running 
> with 1920x1200 at 60. This still needs testing on other graphics cards and 
> with dual link DVI.
> 
> There is no Maintainers entry for nouveau.
> 
> Hauke Mehrtens (2):
>   drm/nouveau: activate dual link TMDS links only when possible
>   drm/nouveau: increase max pixel clock to 225 MHZ for HDMI
> 
>  drivers/gpu/drm/nouveau/nouveau_connector.c      | 6 ++++--
>  drivers/gpu/drm/nouveau/nv50_display.c           | 8 ++++----
>  drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c | 2 +-
>  drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c  | 2 +-
>  4 files changed, 10 insertions(+), 8 deletions(-)
> 

Hi Ben,

Some people in the IRC suggested you should look at these patches.

There are still some parts in the code with something like "if
(pixel_lock > 165MHz)", I haven't changed that because that did not
affected me and I do not know in which situations this gets called.

Hauke

On 18 August 2015 at 04:04, Hauke Mehrtens <hauke at hauke-m.de>
wrote:
> On 08/08/2015 07:01 PM, Hauke Mehrtens wrote:
>> These patches are adding support for outputting 2560x1440 at 56 over
HDMI.
>> This needs a pixel clock of 225 MHz which was not supported before.
>>
>> This was tested in a dual monitor setup with a GF114 (GTX 560 TI) and
>> one HDMI monitor running with 2560x1440 at 56 and one DVI monitor
running
>> with 1920x1200 at 60. This still needs testing on other graphics cards
and
>> with dual link DVI.
Out of curiosity, what mode does the VBIOS select to display the
system's boot messages?

Ben.
>>
>> There is no Maintainers entry for nouveau.
>>
>> Hauke Mehrtens (2):
>>   drm/nouveau: activate dual link TMDS links only when possible
>>   drm/nouveau: increase max pixel clock to 225 MHZ for HDMI
>>
>>  drivers/gpu/drm/nouveau/nouveau_connector.c      | 6 ++++--
>>  drivers/gpu/drm/nouveau/nv50_display.c           | 8 ++++----
>>  drivers/gpu/drm/nouveau/nvkm/engine/disp/gf110.c | 2 +-
>>  drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c  | 2 +-
>>  4 files changed, 10 insertions(+), 8 deletions(-)
>>
>
>
> Hi Ben,
>
> Some people in the IRC suggested you should look at these patches.
>
> There are still some parts in the code with something like "if
> (pixel_lock > 165MHz)", I haven't changed that because that did
not
> affected me and I do not know in which situations this gets called.
>
> Hauke
> _______________________________________________
> Nouveau mailing list
> Nouveau at lists.freedesktop.org
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