Am Dienstag, den 01.12.2020, 11:37 +0100 schrieb Martin Kepplinger:
Add interconnect support to mxsfb so that it is able to request enough bandwidth to DDR for display output to work.
Signed-off-by: Martin Kepplinger martin.kepplinger@puri.sm
drivers/gpu/drm/mxsfb/mxsfb_drv.c | 33 +++++++++++++++++++++++++++++++ drivers/gpu/drm/mxsfb/mxsfb_drv.h | 2 ++ drivers/gpu/drm/mxsfb/mxsfb_kms.c | 13 ++++++++++++ 3 files changed, 48 insertions(+)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index 6faf17b6408d..b05e8e5f1e38 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -15,6 +15,7 @@ #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> +#include <linux/interconnect.h>
#include <drm/drm_atomic_helper.h> #include <drm/drm_bridge.h> @@ -311,6 +312,34 @@ static const struct of_device_id mxsfb_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, mxsfb_dt_ids);
+static int mxsfb_init_icc(struct platform_device *pdev) +{
- struct drm_device *drm = platform_get_drvdata(pdev);
- struct mxsfb_drm_private *mxsfb = drm->dev_private;
- int ret;
- /* Optional interconnect request */
- mxsfb->icc_path = devm_of_icc_get(&pdev->dev, "lcdif-dram");
- if (IS_ERR(mxsfb->icc_path)) {
ret = PTR_ERR(mxsfb->icc_path);if (ret == -EPROBE_DEFER)return ret;mxsfb->icc_path = NULL;dev_dbg(drm->dev,"No interconnect may cause display underflows!\n");- }
- ret = icc_set_bw(mxsfb->icc_path, 0, MBps_to_icc(700));
Shouldn't this be proportional to the current mode, instead of a fixed value? 700MB looks like 1080p@60Hz@32bpp with a bit of headroom, but there are many valid use-cases where significantly smaller displays are connected to the eLCDIF. Also it doesn't cover the case where an overlay is active, which needs additional bandwidth.
- if (ret) {
dev_err(drm->dev, "%s: icc_set_bw failed: %d\n", __func__, ret);return ret;- }
- return 0;
+}
[...]
#include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> @@ -310,6 +311,12 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc, struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev); struct drm_device *drm = mxsfb->drm; dma_addr_t paddr;
- int ret;
- ret = icc_enable(mxsfb->icc_path);
- if (ret)
dev_err_ratelimited(drm->dev, "%s: icc_enable failed: %d\n",__func__, ret);
Why ratelimited? I wouldn't expect atomic enable/disable to be called often enough for this to make any difference.
Regards, Lucas
pm_runtime_get_sync(drm->dev); mxsfb_enable_axi_clk(mxsfb);