On Thu, 2022-03-17 at 20:02 +0800, Rex-BC Chen wrote:
> Hello Xinlei,
>
> On Thu, 2022-03-17 at 15:53 +0800, xinlei.lee@xxxxxxxxxxxx wrote:
> > From: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> >
> > In order to match the changes of "Use the drm_panel_bridge API",
> > the poweron/poweroff of dsi is extracted from enable/disable and
> > defined as new funcs (pre_enable/post_disable).
> >
> > Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the
> > drm_panel_bridge
> > API")
> >
> > Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> > Signed-off-by: Xinlei Lee <xinlei.lee@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/mediatek/mtk_dsi.c | 45 +++++++++++++++++---------
> > --
> > --
> > 1 file changed, 26 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 262c027d8c2f..e33caaca11a7 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -679,16 +679,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> > *dsi)
> > if (--dsi->refcount != 0)
> > return;
> >
> > - /*
> > - * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
> > - * mtk_dsi_stop() should be called after
> > mtk_drm_crtc_atomic_disable(),
> > - * which needs irq for vblank, and mtk_dsi_stop() will disable
> > irq.
> > - * mtk_dsi_start() needs to be called in
> > mtk_output_dsi_enable(),
> > - * after dsi is fully set.
> > - */
> > - mtk_dsi_stop(dsi);
> > -
> > - mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
> > mtk_dsi_reset_engine(dsi);
> > mtk_dsi_lane0_ulp_mode_enter(dsi);
> > mtk_dsi_clk_ulp_mode_enter(dsi);
> > @@ -703,17 +693,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> > *dsi)
> >
> > static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> > {
> > - int ret;
> > -
> > if (dsi->enabled)
> > return;
> >
> > - ret = mtk_dsi_poweron(dsi);
> > - if (ret < 0) {
> > - DRM_ERROR("failed to power on dsi\n");
> > - return;
> > - }
> > -
> > mtk_dsi_set_mode(dsi);
> > mtk_dsi_clk_hs_mode(dsi, 1);
> >
> > @@ -727,7 +709,16 @@ static void mtk_output_dsi_disable(struct
> > mtk_dsi *dsi)
> > if (!dsi->enabled)
> > return;
> >
> > - mtk_dsi_poweroff(dsi);
> > + /*
> > + * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
>
> Why they are asymmetric?
>
> > + * mtk_dsi_stop() should be called after
> > mtk_drm_crtc_atomic_disable(),
> > + * which needs irq for vblank, and mtk_dsi_stop() will disable
> > irq.
> > + * mtk_dsi_start() needs to be called in
> > mtk_output_dsi_enable(),
> > + * after dsi is fully set.
> > + */
> > + mtk_dsi_stop(dsi);
> > +
> > + mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
> >
> > dsi->enabled = false;
> > }
> > @@ -765,10 +756,26 @@ static void mtk_dsi_bridge_enable(struct
> > drm_bridge *bridge)
> > mtk_output_dsi_enable(dsi);
> > }
> >
> > +static void mtk_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> > +{
> > + struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> > +
> > + mtk_dsi_poweron(dsi);
>
> Should you handle the error of mtk_dsi_poweron?
> If you failed to mtk_dsi_bridge_pre_enable and do
> mtk_dsi_bridge_enable,
> what will happend?
>
> > +}
> > +
> > +static void mtk_dsi_bridge_post_disable(struct drm_bridge *bridge)
> > +{
> > + struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> > +
> > + mtk_dsi_poweroff(dsi);
>
> If you failed to mtk_dsi_bridge_disable and you do
> mtk_dsi_bridge_post_disable,
> what will happend?
> Do you need to handle this?
>
> BRs,
> Rex
>
> > +}
> > +
> > static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
> > .attach = mtk_dsi_bridge_attach,
> > .disable = mtk_dsi_bridge_disable,
> > .enable = mtk_dsi_bridge_enable,
> > + .pre_enable = mtk_dsi_bridge_pre_enable,
> > + .post_disable = mtk_dsi_bridge_post_disable,
> > .mode_set = mtk_dsi_bridge_mode_set,
> > };
> >
>
>
Hi Rex:
Thanks for your review!
1.Why they are asymmetric?
=>My understanding mtk_dsi_stop() and mtk_dsi_start() is to make dsi
switch from LP11 and HS mode.DSI has two working modes:
If it is cmd mode, the data sent is sent by LP11, and dsi_start is just
a signal. In this mode, dsi_stop is not required after sending cmd.
If it is video mode, because the data needs to be sent in HS mode,
dsi_start is required to make dsi enter HS mode from LP11. After
suspend, drm will call dsi_disable, and call dsi_stop to make dsi
return from HS mode to LP11 state.
Therefore mtk_dsi_stop() and mtk_dsi_start() are asymmetric.
For example, in the dsi_host_transfer function, only dsi_stop has no
dsi_start operation.
2.
Because the return type of pre_enable & post_disable in common code is
void type. If there is an error, it will be processed in
poweron/poweroff, and the error message will be printed.
Do you mean that pre_enable & post_disable needs to accept the
poweron/poweroff error return value and then print the error log?
3.
If pre_enable fails, there is only a problem with the dsi module, and
it does not affect the execution of other modules and enable funcs
under drm.
Same goes for post_disable & disable.
Best Regrds!
xinlei
