Re: [PATCH v2 44/50] drm/omap: dpi: Register a drm_bridge

Hi Hans,

On Tue, Aug 27, 2019 at 11:07:56AM +0200, Hans Verkuil wrote:

Hi Laurent,

I tried this series with my Pandaboard, but it broke my Pandaboard. After doing a git bisect it ended up with this patch as the culprit.

If I boot my Pandaboard I get this:

[ 3.271881] omapdss_dss 58000000.dss: 58000000.dss supply vdda_video not found, using dummy regulator [ 3.285369] omapdss_dss 58000000.dss: 58000000.dss supply vdda_video not found, using dummy regulator [ 24.286773] rcu: INFO: rcu_sched self-detected stall on CPU [ 24.292388] rcu: 0-...!: (1306 ticks this GP) idle=6b6/1/0x40000002 softirq=85/85 fqs=19 [ 24.300689] (t=2100 jiffies g=-1063 q=10) [ 24.304809] rcu: rcu_sched kthread starved for 2058 jiffies! g-1063 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 [ 24.315124] rcu: RCU grace-period kthread stack dump: [ 24.315124] rcu_sched I 0 10 2 0x00000000 [ 24.325805] [<c09b7130>] (__schedule) from [<c09b73a8>] (schedule+0x40/0xc0) [ 24.332885] [<c09b73a8>] (schedule) from [<c09ba9d0>] (schedule_timeout+0x174/0x2a8) [ 24.340698] [<c09ba9d0>] (schedule_timeout) from [<c01943a4>] (rcu_gp_kthread+0x49c/0x9f4) [ 24.349121] [<c01943a4>] (rcu_gp_kthread) from [<c01559f8>] (kthread+0x13c/0x148) [ 24.356658] [<c01559f8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c) [ 24.363922] Exception stack(0xe70a1fb0 to 0xe70a1ff8) [ 24.363922] 1fa0: 00000000 00000000 00000000 00000000 [ 24.363922] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 24.385437] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 24.392089] NMI backtrace for cpu 0 [ 24.392120] CPU: 0 PID: 105 Comm: kworker/0:2 Not tainted 5.3.0-rc3-arm #152 [ 24.392120] Hardware name: Generic OMAP4 (Flattened Device Tree) [ 24.408721] Workqueue: events deferred_probe_work_func [ 24.408721] [<c010fd70>] (unwind_backtrace) from [<c010b7e8>] (show_stack+0x10/0x14) [ 24.421783] [<c010b7e8>] (show_stack) from [<c09a054c>] (dump_stack+0x84/0x9c) [ 24.429077] [<c09a054c>] (dump_stack) from [<c09a6ecc>] (nmi_cpu_backtrace+0x8c/0xc0) [ 24.436950] [<c09a6ecc>] (nmi_cpu_backtrace) from [<c09a7014>] (nmi_trigger_cpumask_backtrace+0x114/0x12c) [ 24.446655] [<c09a7014>] (nmi_trigger_cpumask_backtrace) from [<c01961e0>] (rcu_dump_cpu_stacks+0xa4/0xcc) [ 24.456359] [<c01961e0>] (rcu_dump_cpu_stacks) from [<c01952bc>] (rcu_sched_clock_irq+0x608/0x7f8) [ 24.465362] [<c01952bc>] (rcu_sched_clock_irq) from [<c019b21c>] (update_process_times+0x34/0x6c) [ 24.465362] [<c019b21c>] (update_process_times) from [<c01acfcc>] (tick_sched_timer+0x4c/0xa8) [ 24.483001] [<c01acfcc>] (tick_sched_timer) from [<c019c470>] (__hrtimer_run_queues+0x154/0x1fc) [ 24.491851] [<c019c470>] (__hrtimer_run_queues) from [<c019c84c>] (hrtimer_interrupt+0x11c/0x2ac) [ 24.500762] [<c019c84c>] (hrtimer_interrupt) from [<c010f3ac>] (twd_handler+0x30/0x38) [ 24.500762] [<c010f3ac>] (twd_handler) from [<c018959c>] (handle_percpu_devid_irq+0x78/0x138) [ 24.517333] [<c018959c>] (handle_percpu_devid_irq) from [<c0183a60>] (generic_handle_irq+0x24/0x34) [ 24.526458] [<c0183a60>] (generic_handle_irq) from [<c0184028>] (__handle_domain_irq+0x5c/0xb4) [ 24.526458] [<c0184028>] (__handle_domain_irq) from [<c03bbf2c>] (gic_handle_irq+0x58/0x9c) [ 24.526458] [<c03bbf2c>] (gic_handle_irq) from [<c0101a8c>] (__irq_svc+0x6c/0x90) [ 24.526458] Exception stack(0xe6439d68 to 0xe6439db0) [ 24.551177] 9d60: c0f783e8 00000000 00000000 efdb49d0 e647f2e8 efdb7f74 [ 24.551177] 9d80: e647f2e8 00000000 e647f294 e647f2e8 00000000 efdb5a98 00000000 e6439db8 [ 24.551177] 9da0: c04e9830 c04e9858 20000153 ffffffff [ 24.577789] [<c0101a8c>] (__irq_svc) from [<c04e9858>] (of_drm_find_bridge+0x40/0x84) [ 24.577789] [<c04e9858>] (of_drm_find_bridge) from [<c0526608>] (omapdss_device_init_output+0x38/0x140) [ 24.595153] [<c0526608>] (omapdss_device_init_output) from [<c0530294>] (dpi_init_port+0x208/0x294) [ 24.604248] [<c0530294>] (dpi_init_port) from [<c05278c4>] (dss_probe+0x2b4/0x550) [ 24.604248] [<c05278c4>] (dss_probe) from [<c0576c1c>] (platform_drv_probe+0x48/0x98) [ 24.604248] [<c0576c1c>] (platform_drv_probe) from [<c0574eb0>] (really_probe+0xf0/0x2c4) [ 24.627990] [<c0574eb0>] (really_probe) from [<c057520c>] (driver_probe_device+0x60/0x168) [ 24.627990] [<c057520c>] (driver_probe_device) from [<c0573410>] (bus_for_each_drv+0x84/0xc8) [ 24.644866] [<c0573410>] (bus_for_each_drv) from [<c0574d4c>] (__device_attach+0xd4/0x140) [ 24.644866] [<c0574d4c>] (__device_attach) from [<c05740f8>] (bus_probe_device+0x84/0x8c) [ 24.661376] [<c05740f8>] (bus_probe_device) from [<c057456c>] (deferred_probe_work_func+0x64/0x90) [ 24.670379] [<c057456c>] (deferred_probe_work_func) from [<c014f960>] (process_one_work+0x204/0x41c) [ 24.670410] [<c014f960>] (process_one_work) from [<c01510d4>] (worker_thread+0x2a8/0x5bc) [ 24.687805] [<c01510d4>] (worker_thread) from [<c01559f8>] (kthread+0x13c/0x148) [ 24.687805] [<c01559f8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c) [ 24.702484] Exception stack(0xe6439fb0 to 0xe6439ff8) [ 24.702484] 9fa0: 00000000 00000000 00000000 00000000 [ 24.702484] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 24.723999] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000

I can send my .config upon request if needed.

CONFIG_OMAP2_DSS_DPI is 'y', but there is nothing connected to the DPI port.

I've retested this on my pandaboard and couldn't reproduce the issue. As I suspected a problem related to the kernel configuration, I tried building the drivers in the kernel image instead of using modules, and I then got a similar looking crash. I'm investigating it now.

On 8/20/19 3:17 AM, Laurent Pinchart wrote:

...

In order to integrate with a chain of drm_bridge, the internal DPI output has to expose its operations through the drm_bridge API. Register a bridge at initialisation time to do so and remove the omap_dss_device operations that are now unused.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

drivers/gpu/drm/omapdrm/dss/dpi.c | 205 ++++++++++++++++++------------ 1 file changed, 122 insertions(+), 83 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/dpi.c b/drivers/gpu/drm/omapdrm/dss/dpi.c index c167bd1116ec..3874e6b6ec49 100644 --- a/drivers/gpu/drm/omapdrm/dss/dpi.c +++ b/drivers/gpu/drm/omapdrm/dss/dpi.c @@ -21,6 +21,8 @@ #include <linux/string.h> #include <linux/sys_soc.h>

+#include <drm/drm_bridge.h>

#include "dss.h" #include "omapdss.h"

@@ -41,12 +43,10 @@ struct dpi_data { int data_lines;

struct omap_dss_device output;

• struct drm_bridge bridge;

};

-static struct dpi_data *dpi_get_data_from_dssdev(struct omap_dss_device *dssdev) -{

• return container_of(dssdev, struct dpi_data, output);

-} +#define drm_bridge_to_dpi(bridge) container_of(bridge, struct dpi_data, bridge)

/* -----------------------------------------------------------------------------

• Clock Handling and PLL

@@ -354,6 +354,32 @@ static void dpi_config_lcd_manager(struct dpi_data *dpi) dss_mgr_set_lcd_config(&dpi->output, &dpi->mgr_config); }

+static int dpi_clock_update(struct dpi_data *dpi, unsigned long *clock) +{

• int lck_div, pck_div;
• unsigned long fck;
• struct dpi_clk_calc_ctx ctx;
• if (dpi->pll) {

• if (!dpi_pll_clk_calc(dpi, *clock, &ctx))
  

• 	return -EINVAL;
  

• fck = ctx.pll_cinfo.clkout[ctx.clkout_idx];
  

• } else {

• if (!dpi_dss_clk_calc(dpi, *clock, &ctx))
  

• 	return -EINVAL;
  

• fck = ctx.fck;
  

• }
• lck_div = ctx.dispc_cinfo.lck_div;
• pck_div = ctx.dispc_cinfo.pck_div;
• *clock = fck / lck_div / pck_div;
• return 0;

+}

static int dpi_verify_pll(struct dss_pll *pll) { int r; @@ -391,29 +417,76 @@ static void dpi_init_pll(struct dpi_data *dpi) }

/* -----------------------------------------------------------------------------

• • omap_dss_device Operations

• • DRM Bridge Operations
  */

-static int dpi_connect(struct omap_dss_device *src,

•        struct omap_dss_device *dst)
  

+static int dpi_bridge_attach(struct drm_bridge *bridge,

• 	     enum drm_bridge_attach_flags flags)
  

{

• struct dpi_data *dpi = dpi_get_data_from_dssdev(dst);

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge);

• if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))

• return -EINVAL;
  
  

  dpi_init_pll(dpi);

• return omapdss_device_connect(dst->dss, dst, dst->next);

• return drm_bridge_attach(bridge->encoder, dpi->output.next_bridge,

• 		 bridge, flags);
  

}

-static void dpi_disconnect(struct omap_dss_device *src,

• 	   struct omap_dss_device *dst)
  

+static enum drm_mode_status +dpi_bridge_mode_valid(struct drm_bridge *bridge,

•        const struct drm_display_mode *mode)
  

{

• omapdss_device_disconnect(dst, dst->next);

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge);
• unsigned long clock = mode->clock * 1000;
• int ret;
• if (mode->hdisplay % 8 != 0)

• return MODE_BAD_WIDTH;
  

• if (mode->clock == 0)

• return MODE_NOCLOCK;
  

• ret = dpi_clock_update(dpi, &clock);
• if (ret < 0)

• return MODE_CLOCK_RANGE;
  

• return MODE_OK;

+}

+static bool dpi_bridge_mode_fixup(struct drm_bridge *bridge,

• 		   const struct drm_display_mode *mode,
  

• 		   struct drm_display_mode *adjusted_mode)
  

+{

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge);
• unsigned long clock = mode->clock * 1000;
• int ret;
• ret = dpi_clock_update(dpi, &clock);
• if (ret < 0)

• return false;
  

• adjusted_mode->clock = clock / 1000;
• return true;

+}

+static void dpi_bridge_mode_set(struct drm_bridge *bridge,

• 		 const struct drm_display_mode *mode,
  

• 		 const struct drm_display_mode *adjusted_mode)
  

+{

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge);
• mutex_lock(&dpi->lock);
• dpi->pixelclock = adjusted_mode->clock * 1000;
• mutex_unlock(&dpi->lock);

}

-static void dpi_display_enable(struct omap_dss_device *dssdev) +static void dpi_bridge_enable(struct drm_bridge *bridge,

• 	       struct drm_atomic_state *state)
  

{

• struct dpi_data *dpi = dpi_get_data_from_dssdev(dssdev);
• struct omap_dss_device *out = &dpi->output;

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge); int r;

  mutex_lock(&dpi->lock);

@@ -428,7 +501,7 @@ static void dpi_display_enable(struct omap_dss_device *dssdev) if (r) goto err_get_dispc;

• r = dss_dpi_select_source(dpi->dss, dpi->id, out->dispc_channel);

• r = dss_dpi_select_source(dpi->dss, dpi->id, dpi->output.dispc_channel); if (r) goto err_src_sel;

@@ -468,9 +541,10 @@ static void dpi_display_enable(struct omap_dss_device *dssdev) mutex_unlock(&dpi->lock); }

-static void dpi_display_disable(struct omap_dss_device *dssdev) +static void dpi_bridge_disable(struct drm_bridge *bridge,

• 		struct drm_atomic_state *state)
  

{

• struct dpi_data *dpi = dpi_get_data_from_dssdev(dssdev);

• struct dpi_data *dpi = drm_bridge_to_dpi(bridge);

  mutex_lock(&dpi->lock);

@@ -490,71 +564,33 @@ static void dpi_display_disable(struct omap_dss_device *dssdev) mutex_unlock(&dpi->lock); }

-static int dpi_check_timings(struct omap_dss_device *dssdev,

• 	     struct drm_display_mode *mode)
  

-{

• struct dpi_data *dpi = dpi_get_data_from_dssdev(dssdev);
• int lck_div, pck_div;
• unsigned long fck;
• unsigned long pck;
• struct dpi_clk_calc_ctx ctx;
• bool ok;
• if (mode->hdisplay % 8 != 0)

• return -EINVAL;
  

• if (mode->clock == 0)

• return -EINVAL;
  

• if (dpi->pll) {

• ok = dpi_pll_clk_calc(dpi, mode->clock * 1000, &ctx);
  

• if (!ok)
  

• 	return -EINVAL;
  

• fck = ctx.pll_cinfo.clkout[ctx.clkout_idx];
  

• } else {

• ok = dpi_dss_clk_calc(dpi, mode->clock * 1000, &ctx);
  

• if (!ok)
  

• 	return -EINVAL;
  

• fck = ctx.fck;
  

• }
• lck_div = ctx.dispc_cinfo.lck_div;
• pck_div = ctx.dispc_cinfo.pck_div;
• pck = fck / lck_div / pck_div;
• mode->clock = pck / 1000;
• return 0;

-}

-static void dpi_set_timings(struct omap_dss_device *dssdev,

• 	    const struct drm_display_mode *mode)
  

-{

• struct dpi_data *dpi = dpi_get_data_from_dssdev(dssdev);
• DSSDBG("dpi_set_timings\n");
• mutex_lock(&dpi->lock);
• dpi->pixelclock = mode->clock * 1000;
• mutex_unlock(&dpi->lock);

-}

-static const struct omap_dss_device_ops dpi_ops = {

• .connect = dpi_connect,
• .disconnect = dpi_disconnect,
• .enable = dpi_display_enable,
• .disable = dpi_display_disable,
• .check_timings = dpi_check_timings,
• .set_timings = dpi_set_timings,

+static const struct drm_bridge_funcs dpi_bridge_funcs = {

• .attach = dpi_bridge_attach,
• .mode_valid = dpi_bridge_mode_valid,
• .mode_fixup = dpi_bridge_mode_fixup,
• .mode_set = dpi_bridge_mode_set,
• .atomic_enable = dpi_bridge_enable,
• .atomic_disable = dpi_bridge_disable,

};

+static void dpi_bridge_init(struct dpi_data *dpi) +{

• dpi->bridge.funcs = &dpi_bridge_funcs;
• dpi->bridge.of_node = dpi->pdev->dev.of_node;
• dpi->bridge.type = DRM_MODE_CONNECTOR_DPI;
• drm_bridge_add(&dpi->bridge);

+}

+static void dpi_bridge_cleanup(struct dpi_data *dpi) +{

• drm_bridge_remove(&dpi->bridge);

+}

+/* -----------------------------------------------------------------------------

• • Initialisation and Cleanup
• */

/*

• Return a hardcoded channel for the DPI output. This should work for
• current use cases, but this can be later expanded to either resolve

@@ -597,6 +633,8 @@ static int dpi_init_output_port(struct dpi_data *dpi, struct device_node *port) u32 port_num = 0; int r;

• dpi_bridge_init(dpi);
• of_property_read_u32(port, "reg", &port_num); dpi->id = port_num <= 2 ? port_num : 0;

@@ -618,10 +656,9 @@ static int dpi_init_output_port(struct dpi_data *dpi, struct device_node *port) out->type = OMAP_DISPLAY_TYPE_DPI; out->dispc_channel = dpi_get_channel(dpi); out->of_port = port_num;

• out->ops = &dpi_ops; out->owner = THIS_MODULE;

• r = omapdss_device_init_output(out, NULL);

• r = omapdss_device_init_output(out, &dpi->bridge); if (r < 0) return r;

@@ -637,6 +674,8 @@ static void dpi_uninit_output_port(struct device_node *port)

omapdss_device_unregister(out); omapdss_device_cleanup_output(out);

• dpi_bridge_cleanup(dpi);

}

/* -----------------------------------------------------------------------------