| Message ID | 1484656294-6140-5-git-send-email-narmstrong@baylibre.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
Hi Neil, Thank you for the patch. On Tuesday 17 Jan 2017 13:31:34 Neil Armstrong wrote: > Some display pipelines can only provide non-RBG input pixels to the HDMI TX > Controller, this patch takes the pixel format from the plat_data if > provided. > > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> > --- > drivers/gpu/drm/bridge/dw-hdmi.c | 7 +++++-- > include/drm/bridge/dw_hdmi.h | 9 +++++++++ > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c > b/drivers/gpu/drm/bridge/dw-hdmi.c index 8a6a183..fa4147c 100644 > --- a/drivers/gpu/drm/bridge/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/dw-hdmi.c > @@ -1420,8 +1420,11 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct > drm_display_mode *mode) hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = > 0; > hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0; > > - /* TODO: Get input format from IPU (via FB driver interface) */ > - hdmi->hdmi_data.enc_in_format = RGB; > + /* Get input format from plat data or fallback to RGB */ > + if (hdmi->plat_data->input_fmt >= 0) > + hdmi->hdmi_data.enc_in_format = hdmi->plat_data->input_fmt; > + else > + hdmi->hdmi_data.enc_in_format = RGB; This should ideally be queried dynamically. I believe we need to extend the DRM bridge API for this purpose. I might be willing to accept a pdata-based solution in the meantime though. > hdmi->hdmi_data.enc_out_format = RGB; > > diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h > index d6a0ab3..4f426c3 100644 > --- a/include/drm/bridge/dw_hdmi.h > +++ b/include/drm/bridge/dw_hdmi.h > @@ -21,6 +21,14 @@ enum { > DW_HDMI_RES_MAX, > }; > > +enum { > + DW_HDMI_INPUT_FMT_RGB = 0, > + DW_HDMI_INPUT_FMT_YCBCR444, > + DW_HDMI_INPUT_FMT_YCBCR422_16BITS, > + DW_HDMI_INPUT_FMT_YCBCR422_8BITS, > + DW_HDMI_INPUT_FMT_XVYCC444, > +}; How about giving the enum a name and dropping the #define RGB 0 #define YCBCR444 1 #define YCBCR422_16BITS 2 #define YCBCR422_8BITS 3 #define XVYCC444 4 macros from the driver ? Even better, how about using a media bus format code from include/uapi/linux/media-bus-format.h ? We would need an additional colorspace field to express the difference between the YCBCR and XVYCC formats, as both of them are YUV 4:4:4 and map to the same bus format. > enum dw_hdmi_phy_type { > DW_HDMI_PHY_DWC_HDMI_TX_PHY = 0x00, > DW_HDMI_PHY_DWC_MHL_PHY_HEAC = 0xb2, > @@ -68,6 +76,7 @@ struct dw_hdmi_plat_data { > const struct dw_hdmi_plat_data *data); > bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi, > const struct dw_hdmi_plat_data *data); > + int input_fmt; > }; > > int dw_hdmi_probe(struct platform_device *pdev,
Hi Neil, On 17-01-2017 12:31, Neil Armstrong wrote: > Some display pipelines can only provide non-RBG input pixels to the HDMI TX > Controller, this patch takes the pixel format from the plat_data if provided. > > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> > --- > drivers/gpu/drm/bridge/dw-hdmi.c | 7 +++++-- > include/drm/bridge/dw_hdmi.h | 9 +++++++++ > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c > index 8a6a183..fa4147c 100644 > --- a/drivers/gpu/drm/bridge/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/dw-hdmi.c > @@ -1420,8 +1420,11 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode) > hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0; > hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0; > > - /* TODO: Get input format from IPU (via FB driver interface) */ > - hdmi->hdmi_data.enc_in_format = RGB; > + /* Get input format from plat data or fallback to RGB */ > + if (hdmi->plat_data->input_fmt >= 0) > + hdmi->hdmi_data.enc_in_format = hdmi->plat_data->input_fmt; Also not a big fan of this approach, but its better than it was. BTW see relevant discussion about colorspace (this is more in the output path) here [1]. [1] https://patchwork.kernel.org/patch/9495153/ > + else > + hdmi->hdmi_data.enc_in_format = RGB; > > hdmi->hdmi_data.enc_out_format = RGB; > > diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h > index d6a0ab3..4f426c3 100644 > --- a/include/drm/bridge/dw_hdmi.h > +++ b/include/drm/bridge/dw_hdmi.h > @@ -21,6 +21,14 @@ enum { > DW_HDMI_RES_MAX, > }; > > +enum { > + DW_HDMI_INPUT_FMT_RGB = 0, > + DW_HDMI_INPUT_FMT_YCBCR444, > + DW_HDMI_INPUT_FMT_YCBCR422_16BITS, > + DW_HDMI_INPUT_FMT_YCBCR422_8BITS, Hmm, did you test these two? I'm not sure if deep color can be converted using CSC. Best regards, Jose Miguel Abreu > + DW_HDMI_INPUT_FMT_XVYCC444, > +}; > + > enum dw_hdmi_phy_type { > DW_HDMI_PHY_DWC_HDMI_TX_PHY = 0x00, > DW_HDMI_PHY_DWC_MHL_PHY_HEAC = 0xb2, > @@ -68,6 +76,7 @@ struct dw_hdmi_plat_data { > const struct dw_hdmi_plat_data *data); > bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi, > const struct dw_hdmi_plat_data *data); > + int input_fmt; > }; > > int dw_hdmi_probe(struct platform_device *pdev,
Hi Jose, On 01/18/2017 11:28 AM, Jose Abreu wrote: > Hi Neil, > > > On 17-01-2017 12:31, Neil Armstrong wrote: >> Some display pipelines can only provide non-RBG input pixels to the HDMI TX >> Controller, this patch takes the pixel format from the plat_data if provided. >> >> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> >> --- >> drivers/gpu/drm/bridge/dw-hdmi.c | 7 +++++-- >> include/drm/bridge/dw_hdmi.h | 9 +++++++++ >> 2 files changed, 14 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c >> index 8a6a183..fa4147c 100644 >> --- a/drivers/gpu/drm/bridge/dw-hdmi.c >> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c >> @@ -1420,8 +1420,11 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode) >> hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0; >> hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0; >> >> - /* TODO: Get input format from IPU (via FB driver interface) */ >> - hdmi->hdmi_data.enc_in_format = RGB; >> + /* Get input format from plat data or fallback to RGB */ >> + if (hdmi->plat_data->input_fmt >= 0) >> + hdmi->hdmi_data.enc_in_format = hdmi->plat_data->input_fmt; > > Also not a big fan of this approach, but its better than it was. > BTW see relevant discussion about colorspace (this is more in the > output path) here [1]. > > [1] https://patchwork.kernel.org/patch/9495153/ > >> + else >> + hdmi->hdmi_data.enc_in_format = RGB; >> >> hdmi->hdmi_data.enc_out_format = RGB; >> >> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h >> index d6a0ab3..4f426c3 100644 >> --- a/include/drm/bridge/dw_hdmi.h >> +++ b/include/drm/bridge/dw_hdmi.h >> @@ -21,6 +21,14 @@ enum { >> DW_HDMI_RES_MAX, >> }; >> >> +enum { >> + DW_HDMI_INPUT_FMT_RGB = 0, >> + DW_HDMI_INPUT_FMT_YCBCR444, >> + DW_HDMI_INPUT_FMT_YCBCR422_16BITS, >> + DW_HDMI_INPUT_FMT_YCBCR422_8BITS, > > Hmm, did you test these two? I'm not sure if deep color can be > converted using CSC. I simply copied the dw-hdmi internal values. Proper handling of input formats capabilities and output format pixel clock handling should be added sometime. In the meantime, it's worth adding which input is supported. This approach is very limited, should I add a bitmask with all support input formats and select between RGB, YUV444 or YUV422 in dw_hdmi_setup ? > > Best regards, > Jose Miguel Abreu > >> + DW_HDMI_INPUT_FMT_XVYCC444, >> +}; >> + >> enum dw_hdmi_phy_type { >> DW_HDMI_PHY_DWC_HDMI_TX_PHY = 0x00, >> DW_HDMI_PHY_DWC_MHL_PHY_HEAC = 0xb2, >> @@ -68,6 +76,7 @@ struct dw_hdmi_plat_data { >> const struct dw_hdmi_plat_data *data); >> bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi, >> const struct dw_hdmi_plat_data *data); >> + int input_fmt; >> }; >> >> int dw_hdmi_probe(struct platform_device *pdev, > Thanks, Neil
Hi Neil, (CC'ing Hans Verkuil) On Wednesday 18 Jan 2017 12:24:22 Neil Armstrong wrote: > On 01/18/2017 11:28 AM, Jose Abreu wrote: > > On 17-01-2017 12:31, Neil Armstrong wrote: > >> Some display pipelines can only provide non-RBG input pixels to the HDMI > >> TX Controller, this patch takes the pixel format from the plat_data if > >> provided. > >> > >> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> > >> --- > >> > >> drivers/gpu/drm/bridge/dw-hdmi.c | 7 +++++-- > >> include/drm/bridge/dw_hdmi.h | 9 +++++++++ > >> 2 files changed, 14 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c > >> b/drivers/gpu/drm/bridge/dw-hdmi.c index 8a6a183..fa4147c 100644 > >> --- a/drivers/gpu/drm/bridge/dw-hdmi.c > >> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c > >> @@ -1420,8 +1420,11 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, > >> struct drm_display_mode *mode) > >> hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0; > >> hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0; > >> > >> - /* TODO: Get input format from IPU (via FB driver interface) */ > >> - hdmi->hdmi_data.enc_in_format = RGB; > >> + /* Get input format from plat data or fallback to RGB */ > >> + if (hdmi->plat_data->input_fmt >= 0) > >> + hdmi->hdmi_data.enc_in_format = hdmi->plat_data->input_fmt; > > > > Also not a big fan of this approach, but its better than it was. > > BTW see relevant discussion about colorspace (this is more in the > > output path) here [1]. > > > > [1] https://patchwork.kernel.org/patch/9495153/ > > > >> + else > >> + hdmi->hdmi_data.enc_in_format = RGB; > >> > >> hdmi->hdmi_data.enc_out_format = RGB; > >> > >> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h > >> index d6a0ab3..4f426c3 100644 > >> --- a/include/drm/bridge/dw_hdmi.h > >> +++ b/include/drm/bridge/dw_hdmi.h > >> @@ -21,6 +21,14 @@ enum { > >> > >> DW_HDMI_RES_MAX, > >> > >> }; > >> > >> +enum { > >> + DW_HDMI_INPUT_FMT_RGB = 0, > >> + DW_HDMI_INPUT_FMT_YCBCR444, > >> + DW_HDMI_INPUT_FMT_YCBCR422_16BITS, > >> + DW_HDMI_INPUT_FMT_YCBCR422_8BITS, > > > > Hmm, did you test these two? I'm not sure if deep color can be > > converted using CSC. > > I simply copied the dw-hdmi internal values. > Proper handling of input formats capabilities and > output format pixel clock handling should be added sometime. > In the meantime, it's worth adding which input is supported. > > This approach is very limited, should I add a bitmask with all > support input formats and select between RGB, YUV444 or YUV422 > in dw_hdmi_setup ? Ideally the bridge mode set operation should be extended to take format and colorspace information (or another bridge operation should be created for that purpose, I'm still undecided). As that's quite a big change, I'm fine if you start by passing a fixed format and colorspace through platform data. I would however like the format to use the media bus format codes defined in include/uapi/linux/media-bus-format.h. As far as I'm aware we have no colorspace definitions in DRM, so we would need to fix that. V4L2 handles colorspaces, and the API went through several iterations before we got it working, with stupid mistakes that we don't want to repeat here. Jose pointed to https://patchwork.kernel.org/patch/9495153/ as a starting point, and I would like to point out the format and colorspace are two different things. A colorspace is a combination of an encoding and quantization and transfer functions. Hans Verkuil has researched this topic for V4L2 (see https://gstreamer.freedesktop.org/data/events/gstreamer-conference/2015/Hans Verkuil - Colorspaces and HDMI.pdf and https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/colorspaces.html), we *really* want to involve him in this discussion. I believe colorspace information should be shared between V4L2 and DRM the same way we share the media bus formats (We should have done so for 4CCs as well but it's unfortunately too late for that). > >> + DW_HDMI_INPUT_FMT_XVYCC444, > >> +}; > >> + > >> enum dw_hdmi_phy_type { > >> DW_HDMI_PHY_DWC_HDMI_TX_PHY = 0x00, > >> DW_HDMI_PHY_DWC_MHL_PHY_HEAC = 0xb2, > >> @@ -68,6 +76,7 @@ struct dw_hdmi_plat_data { > >> const struct dw_hdmi_plat_data *data); > >> bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi, > >> const struct dw_hdmi_plat_data *data); > >> + int input_fmt; > >> }; > >> > >> int dw_hdmi_probe(struct platform_device *pdev,
Hi Laurent, On 18-01-2017 20:49, Laurent Pinchart wrote: > > Ideally the bridge mode set operation should be extended to take format and > colorspace information (or another bridge operation should be created for that > purpose, I'm still undecided). As that's quite a big change, I'm fine if you > start by passing a fixed format and colorspace through platform data. I would > however like the format to use the media bus format codes defined in > include/uapi/linux/media-bus-format.h. > > As far as I'm aware we have no colorspace definitions in DRM, so we would need > to fix that. V4L2 handles colorspaces, and the API went through several > iterations before we got it working, with stupid mistakes that we don't want > to repeat here. > > Jose pointed to https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.kernel.org_patch_9495153_&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=V21eO0BUlcWrbddiKml5I6ylkiX2ALOHPHmble7kxwI&e= as a starting > point, and I would like to point out the format and colorspace are two > different things. A colorspace is a combination of an encoding and > quantization and transfer functions. Hans Verkuil has researched this topic > for V4L2 (see https://urldefense.proofpoint.com/v2/url?u=https-3A__gstreamer.freedesktop.org_data_events_gstreamer-2Dconference_2015_Hans&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=z9IMQn5gPepKFfsLUwUXiG8MA2s1SBB1jyQDE0JIKdk&e= Verkuil - Colorspaces and HDMI.pdf and > https://urldefense.proofpoint.com/v2/url?u=https-3A__linuxtv.org_downloads_v4l-2Ddvb-2Dapis_uapi_v4l_colorspaces.html&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=QReIV1CxgeALvbP5QObIvfwIh7hjEL8J4fxiATaMVYc&e= ), we > *really* want to involve him in this discussion. > > I believe colorspace information should be shared between V4L2 and DRM the > same way we share the media bus formats (We should have done so for 4CCs as > well but it's unfortunately too late for that). > > Hmm, I am always confusing this :/ So, what I was refering as "color space" is in reality the encoding (pixel encoding). In HDMI the pixel encoding can be RGB 4:4:4, YCbCr 4:4:4, YCbCr 4:2:2 and YCbCr 4:2:0. We also have color depth which can be from 8-bit to 16-bit. Besides this there is also colorimetry. I've used media-bus-format.h to successfully pass information across a V4L2 driver but I've used it in BGR24 only, which is RGB 4:4:4 8 bit, which in media-bust-format.h would correspond to MEDIA_BUS_FMT_BGR888_1X24. So, I don't know exactly what is the support for other encodings and what if there's support for color depth. If there is then great, but if not then support for this should also be added. DRM already parses successfully the supported encodings from EDID and stores them in a structure. Note that this is the output encoding, not the input one. We can still have RGB as input and then output at YCbCr using CSC. The missing point is the selection of encoding (either from userspace or from some sort of automatic mechanism by the kernel). Best regards, Jose Miguel Abreu
On 01/19/17 16:21, Jose Abreu wrote: > Hi Laurent, > > > On 18-01-2017 20:49, Laurent Pinchart wrote: >> >> Ideally the bridge mode set operation should be extended to take format and >> colorspace information (or another bridge operation should be created for that >> purpose, I'm still undecided). As that's quite a big change, I'm fine if you >> start by passing a fixed format and colorspace through platform data. I would >> however like the format to use the media bus format codes defined in >> include/uapi/linux/media-bus-format.h. >> >> As far as I'm aware we have no colorspace definitions in DRM, so we would need >> to fix that. V4L2 handles colorspaces, and the API went through several >> iterations before we got it working, with stupid mistakes that we don't want >> to repeat here. >> >> Jose pointed to https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.kernel.org_patch_9495153_&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=V21eO0BUlcWrbddiKml5I6ylkiX2ALOHPHmble7kxwI&e= as a starting >> point, and I would like to point out the format and colorspace are two >> different things. A colorspace is a combination of an encoding and >> quantization and transfer functions. Hans Verkuil has researched this topic >> for V4L2 (see https://urldefense.proofpoint.com/v2/url?u=https-3A__gstreamer.freedesktop.org_data_events_gstreamer-2Dconference_2015_Hans&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=z9IMQn5gPepKFfsLUwUXiG8MA2s1SBB1jyQDE0JIKdk&e= Verkuil - Colorspaces and HDMI.pdf and >> https://urldefense.proofpoint.com/v2/url?u=https-3A__linuxtv.org_downloads_v4l-2Ddvb-2Dapis_uapi_v4l_colorspaces.html&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=BkyajeUCra1JNwll2fmexnvnkIDglOZPocC1ibkiNCQ&s=QReIV1CxgeALvbP5QObIvfwIh7hjEL8J4fxiATaMVYc&e= ), we >> *really* want to involve him in this discussion. >> >> I believe colorspace information should be shared between V4L2 and DRM the >> same way we share the media bus formats (We should have done so for 4CCs as >> well but it's unfortunately too late for that). >> >> > > Hmm, I am always confusing this :/ So, what I was refering as > "color space" is in reality the encoding (pixel encoding). In > HDMI the pixel encoding can be RGB 4:4:4, YCbCr 4:4:4, YCbCr > 4:2:2 and YCbCr 4:2:0. We also have color depth which can be from > 8-bit to 16-bit. Besides this there is also colorimetry. > > I've used media-bus-format.h to successfully pass information > across a V4L2 driver but I've used it in BGR24 only, which is RGB > 4:4:4 8 bit, which in media-bust-format.h would correspond to > MEDIA_BUS_FMT_BGR888_1X24. So, I don't know exactly what is the > support for other encodings and what if there's support for color > depth. If there is then great, but if not then support for this > should also be added. > > DRM already parses successfully the supported encodings from EDID > and stores them in a structure. Note that this is the output > encoding, not the input one. We can still have RGB as input and > then output at YCbCr using CSC. The missing point is the > selection of encoding (either from userspace or from some sort of > automatic mechanism by the kernel). The list of supported encodings for video capture depends on the HW capabilities. So the driver will list the supported formats (ENUMFMT) and userspace then selects a format (S_FMT) from that list. Most HDMI receivers can convert the input to various RGB/YCbCr formats. Deep color support for HDMI has not been added (surprisingly nobody needed it apparently), but it is pretty easy: new V4L2_PIX_FMT defines should be added for those. When talking about RGB/YCbCr I prefer the term 'color encoding', since this has nothing to do with colorspaces (sRGB. AdobeRGB, BT.2020, etc.) Regards, Hans
Hi Hans and Jose, On Thursday 19 Jan 2017 16:30:57 Hans Verkuil wrote: > On 01/19/17 16:21, Jose Abreu wrote: > > On 18-01-2017 20:49, Laurent Pinchart wrote: > >> Ideally the bridge mode set operation should be extended to take format > >> and colorspace information (or another bridge operation should be created > >> for that purpose, I'm still undecided). As that's quite a big change, I'm > >> fine if you start by passing a fixed format and colorspace through > >> platform data. I would however like the format to use the media bus > >> format codes defined in include/uapi/linux/media-bus-format.h. > >> > >> As far as I'm aware we have no colorspace definitions in DRM, so we would > >> need to fix that. V4L2 handles colorspaces, and the API went through > >> several iterations before we got it working, with stupid mistakes that > >> we don't want to repeat here. > >> > >> Jose pointed to > >> https://patchwork.kernel.org/patch/9495153/ as a starting point, and I > >> would like to point out the format and colorspace are two different > >> things. A colorspace is a combination of an encoding and quantization > >> and transfer functions. Hans Verkuil has researched this topic for V4L2 > >> (see https://gstreamer.freedesktop.org/data/events/gstreamer-> >> conference/2015/Hans Verkuil - Colorspaces and HDMI.pdf and > >> https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/colorspaces.html), we > >> *really* want to involve him in this discussion. > >> > >> I believe colorspace information should be shared between V4L2 and DRM > >> the same way we share the media bus formats (We should have done so for > >> 4CCs as well but it's unfortunately too late for that). > > > > Hmm, I am always confusing this :/ So, what I was refering as > > "color space" is in reality the encoding (pixel encoding). In > > HDMI the pixel encoding can be RGB 4:4:4, YCbCr 4:4:4, YCbCr > > 4:2:2 and YCbCr 4:2:0. We also have color depth which can be from > > 8-bit to 16-bit. Besides this there is also colorimetry. There's two separate concepts here, the color encoding and the pixel format. The color encoding defines how non-linear R'G'B' is transformed to non-linear Y'CbCr (or whether to stick to R'G'B' of course). It's a mathematical formula, and along with the quantization defines how the numerical Y'CbCr values are obtained. The pixel format then defines the number of bits per sample, as well as the subsampling factors. The media bus codes thus roughly correspond to pixel formats (although they also define whether the color encoding uses RGB or YCbCr, but don't define the color encoding itself or the quantization method). > > I've used media-bus-format.h to successfully pass information > > across a V4L2 driver but I've used it in BGR24 only, which is RGB > > 4:4:4 8 bit, which in media-bust-format.h would correspond to > > MEDIA_BUS_FMT_BGR888_1X24. So, I don't know exactly what is the > > support for other encodings and what if there's support for color > > depth. If there is then great, but if not then support for this > > should also be added. We have a bunch of YUV media bus formats defined in the kernel (see https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/subdev-formats.html#v4l2-mbus-pixelcode). We're missing some that would be needed here (namely YUV 4:4:4 in 12bpp and I believe the 4:2:0 formats), but it's just a matter of adding new definitions with the related documentation. > > DRM already parses successfully the supported encodings from EDID > > and stores them in a structure. Note that this is the output > > encoding, not the input one. We can still have RGB as input and > > then output at YCbCr using CSC. The missing point is the > > selection of encoding (either from userspace or from some sort of > > automatic mechanism by the kernel). We need to select both the input and output formats and encodings, and, yes, I believe that at least the output format and encoding should come from userspace. > The list of supported encodings for video capture depends on the HW > capabilities. So the driver will list the supported formats (ENUMFMT) > and userspace then selects a format (S_FMT) from that list. Please note that this is about HDMI encoders and the DRM/KMS subsystem :-) > Most HDMI receivers can convert the input to various RGB/YCbCr formats. > > Deep color support for HDMI has not been added (surprisingly nobody needed > it apparently), but it is pretty easy: new V4L2_PIX_FMT defines should be > added for those. New media bus formats in this case. > When talking about RGB/YCbCr I prefer the term 'color encoding', since > this has nothing to do with colorspaces (sRGB. AdobeRGB, BT.2020, etc.)
diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c index 8a6a183..fa4147c 100644 --- a/drivers/gpu/drm/bridge/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/dw-hdmi.c @@ -1420,8 +1420,11 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode) hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0; hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0; - /* TODO: Get input format from IPU (via FB driver interface) */ - hdmi->hdmi_data.enc_in_format = RGB; + /* Get input format from plat data or fallback to RGB */ + if (hdmi->plat_data->input_fmt >= 0) + hdmi->hdmi_data.enc_in_format = hdmi->plat_data->input_fmt; + else + hdmi->hdmi_data.enc_in_format = RGB; hdmi->hdmi_data.enc_out_format = RGB; diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h index d6a0ab3..4f426c3 100644 --- a/include/drm/bridge/dw_hdmi.h +++ b/include/drm/bridge/dw_hdmi.h @@ -21,6 +21,14 @@ enum { DW_HDMI_RES_MAX, }; +enum { + DW_HDMI_INPUT_FMT_RGB = 0, + DW_HDMI_INPUT_FMT_YCBCR444, + DW_HDMI_INPUT_FMT_YCBCR422_16BITS, + DW_HDMI_INPUT_FMT_YCBCR422_8BITS, + DW_HDMI_INPUT_FMT_XVYCC444, +}; + enum dw_hdmi_phy_type { DW_HDMI_PHY_DWC_HDMI_TX_PHY = 0x00, DW_HDMI_PHY_DWC_MHL_PHY_HEAC = 0xb2, @@ -68,6 +76,7 @@ struct dw_hdmi_plat_data { const struct dw_hdmi_plat_data *data); bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi, const struct dw_hdmi_plat_data *data); + int input_fmt; }; int dw_hdmi_probe(struct platform_device *pdev,
Some display pipelines can only provide non-RBG input pixels to the HDMI TX Controller, this patch takes the pixel format from the plat_data if provided. Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> --- drivers/gpu/drm/bridge/dw-hdmi.c | 7 +++++-- include/drm/bridge/dw_hdmi.h | 9 +++++++++ 2 files changed, 14 insertions(+), 2 deletions(-)