On 06.08.2018 21:31, Leonard Crestez wrote:

LCDIF will repeatedly display data from CUR_BUF and set CUR_BUF to NEXT_BUF when done. Since we are only ever writing to NEXT_BUF the display will show an initial corrupt frame.

Fix by writing the FB paddr to both CUR_BUF and NEXT_BUF when activating the CRTC.

Really like how this patch set evolves! Only some minor thing below...

Signed-off-by: Leonard Crestez leonard.crestez@nxp.com

drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 42 +++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c index 0abe77675b76..db3ff5bde122 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c @@ -194,15 +194,31 @@ static int mxsfb_reset_block(void __iomem *reset_addr) return ret;

return clear_poll_bit(reset_addr, MODULE_CLKGATE); }

+static dma_addr_t mxsfb_get_fb_paddr(struct mxsfb_drm_private *mxsfb) +{

• struct drm_framebuffer *fb = mxsfb->pipe.plane.state->fb;
• struct drm_gem_cma_object *gem;
• if (!fb)

• return 0;
  

• gem = drm_fb_cma_get_gem_obj(fb, 0);
• if (!gem)

• return 0;
  

• return gem->paddr;

+}

static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb) { struct drm_display_mode *m = &mxsfb->pipe.crtc.state->adjusted_mode; const u32 bus_flags = mxsfb->connector.display_info.bus_flags; u32 vdctrl0, vsync_pulse_len, hsync_pulse_len;

• dma_addr_t paddr; int err;

  /*

  • It seems, you can't re-program the controller if it is still
  • running. This may lead to shifted pictures (FIFO issue?), so

@@ -268,10 +284,16 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb) mxsfb->base + LCDC_VDCTRL3);

writel(SET_DOTCLK_H_VALID_DATA_CNT(m->hdisplay), mxsfb->base + LCDC_VDCTRL4);

• /* Update cur_buf as well to avoid an initial corrupt frame */
• paddr = mxsfb_get_fb_paddr(mxsfb);
• if (paddr) {

• writel(paddr, mxsfb->base + mxsfb->devdata->cur_buf);
  

• writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
  

• }

Traditionally mxsfb_crtc_mode_set_nofb() was used as a callback to mode_set_nofb. And that callback should not fiddle with the fb (as the name says).

So I rather prefer to move the new bits to mxsfb_crtc_enable(), between mxsfb_crtc_mode_set_nofb() and mxsfb_enable_controller(). It is only cosmetics, but I'd rather prefer to have it in the right place.

Currently the AXI clock is disabled between those functions... I suggest to enable the AXI clock once in mxsfb_crtc_enable(). This puts an end to the unnecessary enable/disable/enable sequence in mxsfb_crtc_enable().

So I suggest to create a patch "drm/mxsfb: simplify AXI clock handling"

--- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c @@ -129,7 +129,6 @@ static void mxsfb_enable_controller(struct mxsfb_drm_private *mxsfb) if (mxsfb->clk_disp_axi) clk_prepare_enable(mxsfb->clk_disp_axi); clk_prepare_enable(mxsfb->clk); - mxsfb_enable_axi_clk(mxsfb);

/* If it was disabled, re-enable the mode again */ writel(CTRL_DOTCLK_MODE, mxsfb->base + LCDC_CTRL + REG_SET); @@ -159,8 +158,6 @@ static void mxsfb_disable_controller(struct mxsfb_drm_private *mxsfb) reg &= ~VDCTRL4_SYNC_SIGNALS_ON; writel(reg, mxsfb->base + LCDC_VDCTRL4);

- mxsfb_disable_axi_clk(mxsfb); - clk_disable_unprepare(mxsfb->clk); if (mxsfb->clk_disp_axi) clk_disable_unprepare(mxsfb->clk_disp_axi); @@ -208,7 +205,6 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb) * running. This may lead to shifted pictures (FIFO issue?), so * first stop the controller and drain its FIFOs. */ - mxsfb_enable_axi_clk(mxsfb);

/* Mandatory eLCDIF reset as per the Reference Manual */ err = mxsfb_reset_block(mxsfb->base); @@ -269,12 +265,11 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)

writel(SET_DOTCLK_H_VALID_DATA_CNT(m->hdisplay), mxsfb->base + LCDC_VDCTRL4); - - mxsfb_disable_axi_clk(mxsfb); }

void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb) { + mxsfb_enable_axi_clk(mxsfb); mxsfb_crtc_mode_set_nofb(mxsfb); mxsfb_enable_controller(mxsfb); } @@ -282,6 +277,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb) void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb) { mxsfb_disable_controller(mxsfb); + mxsfb_disable_axi_clk(mxsfb); }

Then move the above section between mxsfb_crtc_mode_set_nofb() and mxsfb_enable_controller().

-- Stefan

mxsfb_disable_axi_clk(mxsfb); }

void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb) { @@ -287,16 +309,12 @@ void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb) void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb, struct drm_plane_state *state) { struct drm_simple_display_pipe *pipe = &mxsfb->pipe; struct drm_crtc *crtc = &pipe->crtc;

• struct drm_framebuffer *fb = pipe->plane.state->fb; struct drm_pending_vblank_event *event;
• struct drm_gem_cma_object *gem;
• if (!crtc)

• return;
  

• dma_addr_t paddr;

  spin_lock_irq(&crtc->dev->event_lock); event = crtc->state->event; if (event) { crtc->state->event = NULL;

@@ -307,14 +325,12 @@ void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb, drm_crtc_send_vblank_event(crtc, event); } } spin_unlock_irq(&crtc->dev->event_lock);

• if (!fb)

• return;
  

• gem = drm_fb_cma_get_gem_obj(fb, 0);
• mxsfb_enable_axi_clk(mxsfb);
• writel(gem->paddr, mxsfb->base + mxsfb->devdata->next_buf);
• mxsfb_disable_axi_clk(mxsfb);

• paddr = mxsfb_get_fb_paddr(mxsfb);
• if (paddr) {

• mxsfb_enable_axi_clk(mxsfb);
  

• writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
  

• mxsfb_disable_axi_clk(mxsfb);
  

• }

}

On 06.08.2018 21:31, Leonard Crestez wrote:

Adding lcdif nodes to a power domain currently results in black/corrupted screens or hangs because power is not correctly enabled when required.

Ensure power is on when display is active by adding pm_runtime_get/put_sync to mxsfb_pipe_enable/disable.

Signed-off-by: Leonard Crestez leonard.crestez@nxp.com

Reviewed-by: Stefan Agner stefan@agner.ch

---

drivers/gpu/drm/mxsfb/mxsfb_drv.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index ffe5137ccaf8..68d79f5dc0d3 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -101,23 +101,27 @@ static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = { static void mxsfb_pipe_enable(struct drm_simple_display_pipe *pipe, struct drm_crtc_state *crtc_state, struct drm_plane_state *plane_state) { struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe);

• struct drm_device *drm = pipe->plane.dev;

• pm_runtime_get_sync(drm->dev); drm_panel_prepare(mxsfb->panel); mxsfb_crtc_enable(mxsfb); drm_panel_enable(mxsfb->panel);

}

static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe) { struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe);

• struct drm_device *drm = pipe->plane.dev;

  drm_panel_disable(mxsfb->panel); mxsfb_crtc_disable(mxsfb); drm_panel_unprepare(mxsfb->panel);

• pm_runtime_put_sync(drm->dev);

}

static void mxsfb_pipe_update(struct drm_simple_display_pipe *pipe, struct drm_plane_state *plane_state) {

On 06.08.2018 21:31, Leonard Crestez wrote:

Since power to the lcdif block can be lost on suspend implement PM_SLEEP_OPS using drm_mode_config_helper_suspend/resume to save/restore the current mode.

Signed-off-by: Leonard Crestez leonard.crestez@nxp.com

Reviewed-by: Stefan Agner stefan@agner.ch

---

drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index 68d79f5dc0d3..d797dfd40d98 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -416,17 +416,38 @@ static int mxsfb_remove(struct platform_device *pdev) drm_dev_unref(drm);

return 0; }

+#ifdef CONFIG_PM_SLEEP +static int mxsfb_suspend(struct device *dev) +{

•   struct drm_device *drm = dev_get_drvdata(dev);
  

•   return drm_mode_config_helper_suspend(drm);
  

+}

+static int mxsfb_resume(struct device *dev) +{

•   struct drm_device *drm = dev_get_drvdata(dev);
  

•   return drm_mode_config_helper_resume(drm);
  

+} +#endif

+static const struct dev_pm_ops mxsfb_pm_ops = {

•   SET_SYSTEM_SLEEP_PM_OPS(mxsfb_suspend, mxsfb_resume)
  

+};

static struct platform_driver mxsfb_platform_driver = { .probe = mxsfb_probe, .remove = mxsfb_remove, .id_table = mxsfb_devtype, .driver = { .name = "mxsfb", .of_match_table = mxsfb_dt_ids,

• .pm		= &mxsfb_pm_ops,
  

  },

};

module_platform_driver(mxsfb_platform_driver);

On 06.08.2018 21:31, Leonard Crestez wrote:

The lcdif block is only powered on when display is active so plane updates when not enabled are not valid. Writing to an unpowered IP block is mostly ignored but can trigger bus errors on some chips.

Prevent this situation by switching to drm_atomic_helper_commit_tail_rpm and having the drm core ensure atomic_plane_update is only called while the crtc is active. This avoids having to keep track of "enabled" bits inside the mxsfb driver.

This also requires handling the vblank event for disable from mxsfb_pipe_update.

Hm, I don't think this is a new requirement. Simple KMS Helper Reference clearly states that it should be called from update: https://www.kernel.org/doc/html/v4.17/gpu/drm-kms-helpers.html#simple-kms-he...

Probably using drm_atomic_helper_commit_tail_rpm just exacerbates an issue which we haven't seen before...

Since I think it is a general fix, I'd rather prefer have it in a separate commit.

Signed-off-by: Leonard Crestez leonard.crestez@nxp.com Suggested-by: Stefan Agner stefan@agner.ch

---

drivers/gpu/drm/mxsfb/mxsfb_drv.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index d797dfd40d98..5777e730085b 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c @@ -96,10 +96,14 @@ static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = { .fb_create = drm_gem_fb_create, .atomic_check = drm_atomic_helper_check, .atomic_commit = drm_atomic_helper_commit, };

+static const struct drm_mode_config_helper_funcs mxsfb_mode_config_helpers = {

• .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,

+};

static void mxsfb_pipe_enable(struct drm_simple_display_pipe *pipe, struct drm_crtc_state *crtc_state, struct drm_plane_state *plane_state) { struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe); @@ -113,15 +117,25 @@ static void mxsfb_pipe_enable(struct drm_simple_display_pipe *pipe,

static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe) {

Shouldn't that be in mxsfb_pipe_update?

-- Stefan

struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe); struct drm_device *drm = pipe->plane.dev;

• struct drm_crtc *crtc = &pipe->crtc;

• struct drm_pending_vblank_event *event;

  drm_panel_disable(mxsfb->panel); mxsfb_crtc_disable(mxsfb); drm_panel_unprepare(mxsfb->panel); pm_runtime_put_sync(drm->dev);

• spin_lock_irq(&drm->event_lock);

• event = crtc->state->event;

• if (event) {

• crtc->state->event = NULL;
  

• drm_crtc_send_vblank_event(crtc, event);
  

• }

• spin_unlock_irq(&drm->event_lock);

}

static void mxsfb_pipe_update(struct drm_simple_display_pipe *pipe, struct drm_plane_state *plane_state) { @@ -232,10 +246,11 @@ static int mxsfb_load(struct drm_device *drm, unsigned long flags) drm->mode_config.min_width = MXSFB_MIN_XRES; drm->mode_config.min_height = MXSFB_MIN_YRES; drm->mode_config.max_width = MXSFB_MAX_XRES; drm->mode_config.max_height = MXSFB_MAX_YRES; drm->mode_config.funcs = &mxsfb_mode_config_funcs;

• drm->mode_config.helper_private = &mxsfb_mode_config_helpers;

  drm_mode_config_reset(drm);

  pm_runtime_get_sync(drm->dev); ret = drm_irq_install(drm, platform_get_irq(pdev, 0));