Re: radeon + DVI->mDP converter + mDP display blank screen issuesince 3.0

From: Alex Deucher
Date: Fri Mar 23 2012 - 15:42:41 EST


On Fri, Mar 23, 2012 at 3:34 PM, Alex Deucher <alexdeucher@xxxxxxxxx> wrote:
> On Fri, Mar 23, 2012 at 11:44 AM, Lennert Buytenhek
> <buytenh@xxxxxxxxxxxxxx> wrote:
>> On Fri, Mar 23, 2012 at 10:59:27AM -0400, Alex Deucher wrote:
>>
>>> > Since Linux 3.0, a system with a Radeon HD 5450 (1002:68f9) connected
>>> > to a 27" Apple LED cinema display via an Atlona AT-DP400 Dual Link DVI
>>> > to Mini DisplayPort converter has started to stop giving screen
>>> > output on switching from text mode to graphical framebuffer during
>>> > system startup.
>>> >
>>> > I finally had some time to look at this, and it seems to have stopped
>>> > working after this commit:
>>> >
>>> >        commit df271bec805b42527d864777ed035fcbb42e76c0
>>> >        Author: Alex Deucher <alexdeucher@xxxxxxxxx>
>>> >        Date:   Fri May 20 04:34:15 2011 -0400
>>> >
>>> >            drm/radeon/kms: properly handle bpc >8 in atom command tables
>>> >
>>> >            Signed-off-by: Alex Deucher <alexdeucher@xxxxxxxxx>
>>> >            Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
>>> >
>>> > ...and with the patch below (i.e. reverting part of the commit above)
>>> > applied to 3.3 I get screen output again.
>>> >
>>> > Even though the monitor seems to have an 8 bit panel, it reports 10
>>> > bits per channel in its EDID:
>>> >
>>> >        [...]
>>> >        Manufacturer: APP Model 9226 Serial Number 41959462
>>> >        Made week 38 of 2010
>>> >        EDID version: 1.4
>>> >        Digital display
>>> >        10 bits per primary color channel
>>> >        DisplayPort interface
>>> >        Maximum image size: 60 cm x 34 cm
>>> >        [...]
>>> >
>>> > The (active, dual link) DVI->mDP converter spec sheet says it supports
>>> > 24 bit color, and I'm guessing that it can't deal with 30.  Is the
>>> > converter at fault here for passing through the EDID unchanged?
>>> >
>>> > Also, what would be the right way to handle this, a kernel command
>>> > line or module option to limit color depth or something like that?
>>> > ("Buy a video card with DP output." is a valid answer, I suppose.)
>>> >
>>> > I have no clue at all about graphics, and I have no idea whatsoever
>>> > what I'm doing here, but I just wanted to post this somewhere for
>>> > Google to find in case someone else runs into this!
>>>
>>> I've inquired with out display team on how to best handle this.  In
>>> the meantime, it's probably best to just default to 8 bpc.  Does the
>>> attached patch fix your issue?
>>
>> I've been using the patch below in a custom Fedora 17 kernel RPM, and
>> that seems to fix the issue.  Your patch seems to be a superset of
>> this patch, so logically, your patch should do the trick as well. :)
>
> Can you try the attached patch on top of my previous one?

Scratch that. Try this one instead.

Alex

>
> Alex
>
>>
>>
>> thanks,
>> Lennert
>>
>>
>> diff -up linux-3.3.0-1.fc17.x86_64/drivers/gpu/drm/radeon/atombios_crtc.c.orig linux-3.3.0-1.fc17.x86_64/drivers/gpu/drm/radeon/atombios_crtc.c
>> --- linux-3.3.0-1.fc17.x86_64/drivers/gpu/drm/radeon/atombios_crtc.c.orig       2012-03-22 14:52:20.538854547 +0100
>> +++ linux-3.3.0-1.fc17.x86_64/drivers/gpu/drm/radeon/atombios_crtc.c    2012-03-22 14:55:39.740794113 +0100
>> @@ -550,8 +550,6 @@ static u32 atombios_adjust_pll(struct dr
>>                if (encoder->crtc == crtc) {
>>                        radeon_encoder = to_radeon_encoder(encoder);
>>                        connector = radeon_get_connector_for_encoder(encoder);
>> -                       if (connector && connector->display_info.bpc)
>> -                               bpc = connector->display_info.bpc;
>>                        encoder_mode = atombios_get_encoder_mode(encoder);
>>                        is_duallink = radeon_dig_monitor_is_duallink(encoder, mode->clock);
>>                        if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT | ATOM_DEVICE_DFP_SUPPORT)) ||
>> @@ -922,7 +920,6 @@ static void atombios_crtc_set_pll(struct
>>                struct radeon_connector_atom_dig *dig_connector =
>>                        radeon_connector->con_priv;
>>                int dp_clock;
>> -               bpc = connector->display_info.bpc;
>>
>>                switch (encoder_mode) {
>>                case ATOM_ENCODER_MODE_DP_MST:
>>
>>
>>
>>> From 22ca454eb749968f266d6788a5f4778acc08cc66 Mon Sep 17 00:00:00 2001
>>> From: Alex Deucher <alexander.deucher@xxxxxxx>
>>> Date: Fri, 23 Mar 2012 10:54:45 -0400
>>> Subject: [PATCH] drm/radeon/kms/atom: force bpc to 8 for now
>>>
>>> Using the bpc (bits per color) specified by the monitor
>>> can cause problems in some cases.  Until we get a better
>>> handle on how to deal with those cases, just use a bpc of 8.
>>>
>>> Reported-by: Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>
>>> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
>>> Cc: stable@xxxxxxxxxx
>>> ---
>>>  drivers/gpu/drm/radeon/atombios_crtc.c     |    8 +++++---
>>>  drivers/gpu/drm/radeon/atombios_dp.c       |    3 +++
>>>  drivers/gpu/drm/radeon/atombios_encoders.c |    4 ++--
>>>  3 files changed, 10 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
>>> index 083b3ea..b5ff1f7 100644
>>> --- a/drivers/gpu/drm/radeon/atombios_crtc.c
>>> +++ b/drivers/gpu/drm/radeon/atombios_crtc.c
>>> @@ -588,8 +588,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
>>>               if (encoder->crtc == crtc) {
>>>                       radeon_encoder = to_radeon_encoder(encoder);
>>>                       connector = radeon_get_connector_for_encoder(encoder);
>>> -                     if (connector && connector->display_info.bpc)
>>> -                             bpc = connector->display_info.bpc;
>>> +                     /* if (connector && connector->display_info.bpc)
>>> +                             bpc = connector->display_info.bpc; */
>>>                       encoder_mode = atombios_get_encoder_mode(encoder);
>>>                       is_duallink = radeon_dig_monitor_is_duallink(encoder, mode->clock);
>>>                       if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT | ATOM_DEVICE_DFP_SUPPORT)) ||
>>> @@ -965,7 +965,9 @@ static void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode
>>>               struct radeon_connector_atom_dig *dig_connector =
>>>                       radeon_connector->con_priv;
>>>               int dp_clock;
>>> -             bpc = connector->display_info.bpc;
>>> +
>>> +             /* if (connector->display_info.bpc)
>>> +                     bpc = connector->display_info.bpc; */
>>>
>>>               switch (encoder_mode) {
>>>               case ATOM_ENCODER_MODE_DP_MST:
>>> diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
>>> index 6c62be2..c57d856 100644
>>> --- a/drivers/gpu/drm/radeon/atombios_dp.c
>>> +++ b/drivers/gpu/drm/radeon/atombios_dp.c
>>> @@ -405,10 +405,13 @@ static void dp_get_adjust_train(u8 link_status[DP_LINK_STATUS_SIZE],
>>>  /* get bpc from the EDID */
>>>  static int convert_bpc_to_bpp(int bpc)
>>>  {
>>> +#if 0
>>>       if (bpc == 0)
>>>               return 24;
>>>       else
>>>               return bpc * 3;
>>> +#endif
>>> +     return 24;
>>>  }
>>>
>>>  /* get the max pix clock supported by the link rate and lane num */
>>> diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
>>> index 468b874..e607c4d 100644
>>> --- a/drivers/gpu/drm/radeon/atombios_encoders.c
>>> +++ b/drivers/gpu/drm/radeon/atombios_encoders.c
>>> @@ -541,7 +541,7 @@ atombios_dig_encoder_setup(struct drm_encoder *encoder, int action, int panel_mo
>>>               dp_clock = dig_connector->dp_clock;
>>>               dp_lane_count = dig_connector->dp_lane_count;
>>>               hpd_id = radeon_connector->hpd.hpd;
>>> -             bpc = connector->display_info.bpc;
>>> +             /* bpc = connector->display_info.bpc; */
>>>       }
>>>
>>>       /* no dig encoder assigned */
>>> @@ -1159,7 +1159,7 @@ atombios_external_encoder_setup(struct drm_encoder *encoder,
>>>               dp_lane_count = dig_connector->dp_lane_count;
>>>               connector_object_id =
>>>                       (radeon_connector->connector_object_id & OBJECT_ID_MASK) >> OBJECT_ID_SHIFT;
>>> -             bpc = connector->display_info.bpc;
>>> +             /* bpc = connector->display_info.bpc; */
>>>       }
>>>
>>>       memset(&args, 0, sizeof(args));
>>> --
>>> 1.7.7.5
>>>
From 9e2da3bc558a7dab4a9bd497de5cff19dc20a0b5 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@xxxxxxx>
Date: Fri, 23 Mar 2012 15:41:11 -0400
Subject: [PATCH] drm/radeon/kms: improve bpc handling (v2)

Improve handling of bpc (bits per color) in radeon.
In most cases we want 8 except for HDMI, DP, LVDS, and eDP.

v2: handle DP better.

Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/radeon/atombios_crtc.c | 7 +--
drivers/gpu/drm/radeon/atombios_dp.c | 7 +--
drivers/gpu/drm/radeon/atombios_encoders.c | 4 +-
drivers/gpu/drm/radeon/radeon_connectors.c | 56 ++++++++++++++++++++++++++++
drivers/gpu/drm/radeon/radeon_mode.h | 1 +
5 files changed, 63 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index b5ff1f7..2fab38f 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -588,8 +588,7 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
if (encoder->crtc == crtc) {
radeon_encoder = to_radeon_encoder(encoder);
connector = radeon_get_connector_for_encoder(encoder);
- /* if (connector && connector->display_info.bpc)
- bpc = connector->display_info.bpc; */
+ bpc = radeon_get_monitor_bpc(connector);
encoder_mode = atombios_get_encoder_mode(encoder);
is_duallink = radeon_dig_monitor_is_duallink(encoder, mode->clock);
if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT | ATOM_DEVICE_DFP_SUPPORT)) ||
@@ -965,9 +964,7 @@ static void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode
struct radeon_connector_atom_dig *dig_connector =
radeon_connector->con_priv;
int dp_clock;
-
- /* if (connector->display_info.bpc)
- bpc = connector->display_info.bpc; */
+ bpc = radeon_get_monitor_bpc(connector);

switch (encoder_mode) {
case ATOM_ENCODER_MODE_DP_MST:
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index c57d856..cadbb10 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -405,13 +405,10 @@ static void dp_get_adjust_train(u8 link_status[DP_LINK_STATUS_SIZE],
/* get bpc from the EDID */
static int convert_bpc_to_bpp(int bpc)
{
-#if 0
if (bpc == 0)
return 24;
else
return bpc * 3;
-#endif
- return 24;
}

/* get the max pix clock supported by the link rate and lane num */
@@ -463,7 +460,7 @@ static int radeon_dp_get_dp_lane_number(struct drm_connector *connector,
u8 dpcd[DP_DPCD_SIZE],
int pix_clock)
{
- int bpp = convert_bpc_to_bpp(connector->display_info.bpc);
+ int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
int max_link_rate = dp_get_max_link_rate(dpcd);
int max_lane_num = dp_get_max_lane_number(dpcd);
int lane_num;
@@ -482,7 +479,7 @@ static int radeon_dp_get_dp_link_clock(struct drm_connector *connector,
u8 dpcd[DP_DPCD_SIZE],
int pix_clock)
{
- int bpp = convert_bpc_to_bpp(connector->display_info.bpc);
+ int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
int lane_num, max_pix_clock;

if (radeon_connector_encoder_get_dp_bridge_encoder_id(connector) ==
diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index e607c4d..06b209b 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -541,7 +541,7 @@ atombios_dig_encoder_setup(struct drm_encoder *encoder, int action, int panel_mo
dp_clock = dig_connector->dp_clock;
dp_lane_count = dig_connector->dp_lane_count;
hpd_id = radeon_connector->hpd.hpd;
- /* bpc = connector->display_info.bpc; */
+ bpc = radeon_get_monitor_bpc(connector);
}

/* no dig encoder assigned */
@@ -1159,7 +1159,7 @@ atombios_external_encoder_setup(struct drm_encoder *encoder,
dp_lane_count = dig_connector->dp_lane_count;
connector_object_id =
(radeon_connector->connector_object_id & OBJECT_ID_MASK) >> OBJECT_ID_SHIFT;
- /* bpc = connector->display_info.bpc; */
+ bpc = radeon_get_monitor_bpc(connector);
}

memset(&args, 0, sizeof(args));
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index bd05156..71fa389 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -84,6 +84,62 @@ static void radeon_property_change_mode(struct drm_encoder *encoder)
crtc->x, crtc->y, crtc->fb);
}
}
+
+int radeon_get_monitor_bpc(struct drm_connector *connector)
+{
+ struct drm_device *dev = connector->dev;
+ struct radeon_device *rdev = dev->dev_private;
+ struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+ struct radeon_connector_atom_dig *dig_connector;
+ int bpc = 8;
+
+ switch (connector->connector_type) {
+ case DRM_MODE_CONNECTOR_DVII:
+ case DRM_MODE_CONNECTOR_HDMIB:
+ if (radeon_connector->use_digital) {
+ if (drm_detect_hdmi_monitor(radeon_connector->edid)) {
+ if (connector->display_info.bpc)
+ bpc = connector->display_info.bpc;
+ }
+ }
+ break;
+ case DRM_MODE_CONNECTOR_DVID:
+ case DRM_MODE_CONNECTOR_HDMIA:
+ if (drm_detect_hdmi_monitor(radeon_connector->edid)) {
+ if (connector->display_info.bpc)
+ bpc = connector->display_info.bpc;
+ }
+ break;
+ case DRM_MODE_CONNECTOR_DisplayPort:
+ dig_connector = radeon_connector->con_priv;
+ if ((dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT) ||
+ (dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_eDP) ||
+ drm_detect_hdmi_monitor(radeon_connector->edid)) {
+ if (connector->display_info.bpc)
+ bpc = connector->display_info.bpc;
+ }
+ break;
+ case DRM_MODE_CONNECTOR_eDP:
+ case DRM_MODE_CONNECTOR_LVDS:
+ if (connector->display_info.bpc)
+ bpc = connector->display_info.bpc;
+ else if (ASIC_IS_DCE41(rdev) || ASIC_IS_DCE5(rdev)) {
+ struct drm_connector_helper_funcs *connector_funcs =
+ connector->helper_private;
+ struct drm_encoder *encoder = connector_funcs->best_encoder(connector);
+ struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+ struct radeon_encoder_atom_dig *dig = radeon_encoder->enc_priv;
+
+ if (dig->lcd_misc & ATOM_PANEL_MISC_V13_6BIT_PER_COLOR)
+ bpc = 6;
+ else if (dig->lcd_misc & ATOM_PANEL_MISC_V13_8BIT_PER_COLOR)
+ bpc = 8;
+ }
+ break;
+ }
+ return bpc;
+}
+
static void
radeon_connector_update_scratch_regs(struct drm_connector *connector, enum drm_connector_status status)
{
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index f7eb5d8..b2cca6a 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -476,6 +476,7 @@ extern u16 radeon_encoder_get_dp_bridge_encoder_id(struct drm_encoder *encoder);
extern u16 radeon_connector_encoder_get_dp_bridge_encoder_id(struct drm_connector *connector);
extern bool radeon_connector_encoder_is_hbr2(struct drm_connector *connector);
extern bool radeon_connector_is_dp12_capable(struct drm_connector *connector);
+extern int radeon_get_monitor_bpc(struct drm_connector *connector);

extern void radeon_connector_hotplug(struct drm_connector *connector);
extern int radeon_dp_mode_valid_helper(struct drm_connector *connector,
--
1.7.7.5