Messages in this thread | | | From | Dmitry Baryshkov <> | Date | Tue, 30 May 2023 14:44:38 +0300 | Subject | RFC: DSI host capabilities (was: [PATCH RFC 03/10] drm/panel: Add LGD panel driver for Sony Xperia XZ3) |
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On Tue, 30 May 2023 at 10:24, Neil Armstrong <neil.armstrong@linaro.org> wrote: > > Hi Marijn, Dmitry, Caleb, Jessica, > > On 29/05/2023 23:11, Marijn Suijten wrote: > > On 2023-05-22 04:16:20, Dmitry Baryshkov wrote: > > <snip> > >>> + if (ctx->dsi->dsc) { > >> > >> dsi->dsc is always set, thus this condition can be dropped. > > > > I want to leave room for possibly running the panel without DSC (at a > > lower resolution/refresh rate, or at higher power consumption if there > > is enough BW) by not assigning the pointer, if we get access to panel > > documentation: probably one of the magic commands sent in this driver > > controls it but we don't know which. > > I'd like to investigate if DSC should perhaps only be enabled if we > run non certain platforms/socs ? > > I mean, we don't know if the controller supports DSC and those particular > DSC parameters so we should probably start adding something like : > > static drm_dsc_config dsc_params_qcom = {} > > static const struct of_device_id panel_of_dsc_params[] = { > { .compatible = "qcom,sm8150", , .data = &dsc_params_qcom }, > { .compatible = "qcom,sm8250", , .data = &dsc_params_qcom }, > { .compatible = "qcom,sm8350", , .data = &dsc_params_qcom }, > { .compatible = "qcom,sm8450", , .data = &dsc_params_qcom }, > };
I think this would damage the reusability of the drivers. The panel driver does not actually care if the SoC is SM8350, sunxi-something or RCar. Instead it cares about host capabilities.
I think instead we should extend mipi_dsi_host:
#define MIPI_DSI_HOST_MODE_VIDEO BIT(0) #define MIPI_DSI_HOST_MODE_CMD BIT(1) #define MIPI_DSI_HOST_VIDEO_SUPPORTS_COMMANDS BIT(2) // FIXME: do we need to provide additional caps here ?
#define MIPI_DSI_DSC_1_1 BIT(0) #define MIPI_DSI_DSC_1_2 BIT(1) #define MIPI_DSI_DSC_NATIVE_422 BIT(2) #define MIPI_DSI_DSC_NATIVE_420 BIT(3) #define MIPI_DSI_DSC_FRAC_BPP BIT(4) // etc.
struct mipi_dsi_host { // new fields only unsigned long mode_flags; unsigned long dsc_flags; };
Then the panel driver can adapt itself to the host capabilities and (possibly) select one of the internally supported DSC profiles.
> > ... > static int sony_akatsuki_lgd_probe(struct mipi_dsi_device *dsi) > ... > const struct of_device_id *match; > > ... > match = of_match_node(panel_of_dsc_params, of_root); > if (match && match->data) { > dsi->dsc = devm_kzalloc(&dsi->dev, sizeof(*dsc), GFP_KERNEL); > memcpy(dsi->dsc, match->data, sizeof(*dsc)); > } else { > dev_warn(&dsi->dev, "DSI controller is not marked as supporting DSC\n"); > } > ... > } > > and probably bail out if it's a DSC only panel. > > We could alternatively match on the DSI controller's dsi->host->dev instead of the SoC root compatible. > > Neil
-- With best wishes Dmitry
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