From: Frieder Schrempf <[email protected]>
In case the downstream bridge or panel uses DSI transfers before the
DSI host was actually initialized through samsung_dsim_atomic_enable()
which clears the stop state (LP11) mode, all transfers will fail.
This happens with downstream bridges that are controlled by DSI
commands such as the tc358762.
As documented in [1] DSI hosts are expected to allow transfers
outside the normal bridge enable/disable flow.
To fix this make sure that stop state is cleared in
samsung_dsim_host_transfer() which restores the previous
behavior.
We also factor out the common code to enable/disable stop state
to samsung_dsim_set_stop_state().
[1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation
Fixes: 0c14d3130654 ("drm: bridge: samsung-dsim: Fix i.MX8M enable flow to meet spec")
Reported-by: Tim Harvey <[email protected]>
Signed-off-by: Frieder Schrempf <[email protected]>
---
Changes for v2:
* Fix reversed stop state enable/disable in samsung_dsim_set_stop_state()
Hi Tim, could you please give this patch a try and report back if
it fixes your problem? Thanks!
---
drivers/gpu/drm/bridge/samsung-dsim.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 043b8109e64a..73ec60757dbc 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1386,6 +1386,18 @@ static void samsung_dsim_disable_irq(struct samsung_dsim *dsi)
disable_irq(dsi->irq);
}
+static void samsung_dsim_set_stop_state(struct samsung_dsim *dsi, bool enable)
+{
+ u32 reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
+
+ if (enable)
+ reg |= DSIM_FORCE_STOP_STATE;
+ else
+ reg &= ~DSIM_FORCE_STOP_STATE;
+
+ samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
+}
+
static int samsung_dsim_init(struct samsung_dsim *dsi)
{
const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
@@ -1445,15 +1457,12 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
struct drm_bridge_state *old_bridge_state)
{
struct samsung_dsim *dsi = bridge_to_dsi(bridge);
- u32 reg;
if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
samsung_dsim_set_display_mode(dsi);
samsung_dsim_set_display_enable(dsi, true);
} else {
- reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
- reg &= ~DSIM_FORCE_STOP_STATE;
- samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
+ samsung_dsim_set_stop_state(dsi, false);
}
dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
@@ -1463,16 +1472,12 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
struct drm_bridge_state *old_bridge_state)
{
struct samsung_dsim *dsi = bridge_to_dsi(bridge);
- u32 reg;
if (!(dsi->state & DSIM_STATE_ENABLED))
return;
- if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
- reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
- reg |= DSIM_FORCE_STOP_STATE;
- samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
- }
+ if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
+ samsung_dsim_set_stop_state(dsi, true);
dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
}
@@ -1775,6 +1780,8 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
if (ret)
return ret;
+ samsung_dsim_set_stop_state(dsi, false);
+
ret = mipi_dsi_create_packet(&xfer.packet, msg);
if (ret < 0)
return ret;
--
2.41.0
Hi,
On Mon, 24 Jul 2023 17:16:32 +0200, Frieder Schrempf wrote:
> In case the downstream bridge or panel uses DSI transfers before the
> DSI host was actually initialized through samsung_dsim_atomic_enable()
> which clears the stop state (LP11) mode, all transfers will fail.
>
> This happens with downstream bridges that are controlled by DSI
> commands such as the tc358762.
>
> [...]
Thanks, Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-fixes)
[1/1] drm: bridge: samsung-dsim: Fix init during host transfer
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=20c827683de05a6c7e7ae7fae586899690693251
--
Neil
On Mon, Jul 24, 2023 at 8:16 AM Frieder Schrempf <[email protected]> wrote:
>
> From: Frieder Schrempf <[email protected]>
>
> In case the downstream bridge or panel uses DSI transfers before the
> DSI host was actually initialized through samsung_dsim_atomic_enable()
> which clears the stop state (LP11) mode, all transfers will fail.
>
> This happens with downstream bridges that are controlled by DSI
> commands such as the tc358762.
>
> As documented in [1] DSI hosts are expected to allow transfers
> outside the normal bridge enable/disable flow.
>
> To fix this make sure that stop state is cleared in
> samsung_dsim_host_transfer() which restores the previous
> behavior.
>
> We also factor out the common code to enable/disable stop state
> to samsung_dsim_set_stop_state().
>
> [1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation
>
> Fixes: 0c14d3130654 ("drm: bridge: samsung-dsim: Fix i.MX8M enable flow to meet spec")
> Reported-by: Tim Harvey <[email protected]>
> Signed-off-by: Frieder Schrempf <[email protected]>
> ---
> Changes for v2:
> * Fix reversed stop state enable/disable in samsung_dsim_set_stop_state()
>
> Hi Tim, could you please give this patch a try and report back if
> it fixes your problem? Thanks!
> ---
> drivers/gpu/drm/bridge/samsung-dsim.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 043b8109e64a..73ec60757dbc 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1386,6 +1386,18 @@ static void samsung_dsim_disable_irq(struct samsung_dsim *dsi)
> disable_irq(dsi->irq);
> }
>
> +static void samsung_dsim_set_stop_state(struct samsung_dsim *dsi, bool enable)
> +{
> + u32 reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> +
> + if (enable)
> + reg |= DSIM_FORCE_STOP_STATE;
> + else
> + reg &= ~DSIM_FORCE_STOP_STATE;
> +
> + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
> +}
> +
> static int samsung_dsim_init(struct samsung_dsim *dsi)
> {
> const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> @@ -1445,15 +1457,12 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
> struct drm_bridge_state *old_bridge_state)
> {
> struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> - u32 reg;
>
> if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
> samsung_dsim_set_display_mode(dsi);
> samsung_dsim_set_display_enable(dsi, true);
> } else {
> - reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> - reg &= ~DSIM_FORCE_STOP_STATE;
> - samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
> + samsung_dsim_set_stop_state(dsi, false);
> }
>
> dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
> @@ -1463,16 +1472,12 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
> struct drm_bridge_state *old_bridge_state)
> {
> struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> - u32 reg;
>
> if (!(dsi->state & DSIM_STATE_ENABLED))
> return;
>
> - if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
> - reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> - reg |= DSIM_FORCE_STOP_STATE;
> - samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
> - }
> + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
> + samsung_dsim_set_stop_state(dsi, true);
>
> dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
> }
> @@ -1775,6 +1780,8 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
> if (ret)
> return ret;
>
> + samsung_dsim_set_stop_state(dsi, false);
> +
> ret = mipi_dsi_create_packet(&xfer.packet, msg);
> if (ret < 0)
> return ret;
> --
> 2.41.0
>
Frieder,
Sorry for the delay. Yes this resolves the regression I ran into. I
tested it on top of v6.5-rc6 on a gw72xx-0x with a DFROBOT DRF0678 7in
800x480 (Raspberry Pi) display which has the Toshiba TC358762
compatible DSI to DBI bridge.
Let's please get this into v6.5 as soon as possible.
Best regards,
Tim