[Freedreno] [PATCH] drm/msm/dsi: do not install irq handler before power up the host
Dmitry Baryshkov
dmitry.baryshkov at linaro.org
Sat Oct 2 01:10:23 UTC 2021
On 28/09/2021 04:40, Dmitry Baryshkov wrote:
> On 28/09/2021 04:33, abhinavk at codeaurora.org wrote:
>> On 2021-09-27 18:29, Dmitry Baryshkov wrote:
>>> On 28/09/2021 04:19, abhinavk at codeaurora.org wrote:
>>>> On 2021-09-27 18:06, Dmitry Baryshkov wrote:
>>>>> On Tue, 28 Sept 2021 at 03:22, <abhinavk at codeaurora.org> wrote:
>>>>>>
>>>>>> On 2021-09-25 12:43, Dmitry Baryshkov wrote:
>>>>>> > On 21/09/2021 23:52, abhinavk at codeaurora.org wrote:
>>>>>> >> On 2021-09-21 10:47, Dmitry Baryshkov wrote:
>>>>>> >>> Hi,
>>>>>> >>>
>>>>>> >>> On Tue, 21 Sept 2021 at 20:01, <abhinavk at codeaurora.org> wrote:
>>>>>> >>>>
>>>>>> >>>> On 2021-09-21 09:22, Dmitry Baryshkov wrote:
>>>>>> >>>> > The DSI host might be left in some state by the bootloader.
>>>>>> If this
>>>>>> >>>> > state generates an IRQ, it might hang the system by holding
>>>>>> the
>>>>>> >>>> > interrupt line before the driver sets up the DSI host to
>>>>>> the known
>>>>>> >>>> > state.
>>>>>> >>>> >
>>>>>> >>>> > Move the request/free_irq calls into
>>>>>> msm_dsi_host_power_on/_off calls,
>>>>>> >>>> > so that we can be sure that the interrupt is delivered when
>>>>>> the host is
>>>>>> >>>> > in the known state.
>>>>>> >>>> >
>>>>>> >>>> > Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector
>>>>>> support")
>>>>>> >>>> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>>>>> >>>>
>>>>>> >>>> This is a valid change and we have seen interrupt storms in
>>>>>> >>>> downstream
>>>>>> >>>> happening
>>>>>> >>>> when like you said the bootloader leaves the DSI host in unknown
>>>>>> >>>> state.
>>>>>> >>>> Just one question below.
>>>>>> >>>>
>>>>>> >>>> > ---
>>>>>> >>>> > drivers/gpu/drm/msm/dsi/dsi_host.c | 21 ++++++++++++---------
>>>>>> >>>> > 1 file changed, 12 insertions(+), 9 deletions(-)
>>>>>> >>>> >
>>>>>> >>>> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c
>>>>>> >>>> > b/drivers/gpu/drm/msm/dsi/dsi_host.c
>>>>>> >>>> > index e269df285136..cd842347a6b1 100644
>>>>>> >>>> > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
>>>>>> >>>> > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
>>>>>> >>>> > @@ -1951,15 +1951,6 @@ int msm_dsi_host_modeset_init(struct
>>>>>> >>>> > mipi_dsi_host *host,
>>>>>> >>>> > return ret;
>>>>>> >>>> > }
>>>>>> >>>> >
>>>>>> >>>> > - ret = devm_request_irq(&pdev->dev, msm_host->irq,
>>>>>> >>>> > - dsi_host_irq, IRQF_TRIGGER_HIGH |
>>>>>> IRQF_ONESHOT,
>>>>>> >>>> > - "dsi_isr", msm_host);
>>>>>> >>>> > - if (ret < 0) {
>>>>>> >>>> > - DRM_DEV_ERROR(&pdev->dev, "failed to request
>>>>>> IRQ%u: %d\n",
>>>>>> >>>> > - msm_host->irq, ret);
>>>>>> >>>> > - return ret;
>>>>>> >>>> > - }
>>>>>> >>>> > -
>>>>>> >>>> > msm_host->dev = dev;
>>>>>> >>>> > ret = cfg_hnd->ops->tx_buf_alloc(msm_host, SZ_4K);
>>>>>> >>>> > if (ret) {
>>>>>> >>>> > @@ -2413,6 +2404,16 @@ int msm_dsi_host_power_on(struct
>>>>>> mipi_dsi_host
>>>>>> >>>> > *host,
>>>>>> >>>> > if (msm_host->disp_en_gpio)
>>>>>> >>>> > gpiod_set_value(msm_host->disp_en_gpio, 1);
>>>>>> >>>> >
>>>>>> >>>> > + ret = devm_request_irq(&msm_host->pdev->dev,
>>>>>> msm_host->irq,
>>>>>> >>>> > + dsi_host_irq, IRQF_TRIGGER_HIGH |
>>>>>> IRQF_ONESHOT,
>>>>>> >>>> > + "dsi_isr", msm_host);
>>>>>> >>>> > + if (ret < 0) {
>>>>>> >>>> > + DRM_DEV_ERROR(&msm_host->pdev->dev, "failed
>>>>>> to request IRQ%u: %d\n",
>>>>>> >>>> > + msm_host->irq, ret);
>>>>>> >>>> > + return ret;
>>>>>> >>>> > + }
>>>>>> >>>> > +
>>>>>> >>>> > +
>>>>>> >>>>
>>>>>> >>>> Do you want to move this to msm_dsi_host_enable()?
>>>>>> >>>> So without the controller being enabled it is still in unknown
>>>>>> >>>> state?
>>>>>> >>>
>>>>>> >>> msm_dsi_host_power_on() reconfigures the host registers, so
>>>>>> the state
>>>>>> >>> is known at the end of the power_on().
>>>>>> >>>
>>>>>> >>>> Also do you want to do this after dsi0 and dsi1 are
>>>>>> initialized to
>>>>>> >>>> account for
>>>>>> >>>> dual dsi cases?
>>>>>> >>>
>>>>>> >>> I don't think this should matter. The host won't generate 'extra'
>>>>>> >>> interrupts in such case, will it?
>>>>>> >>>
>>>>>> >> We have seen cases where misconfiguration has caused interrupts to
>>>>>> >> storm only
>>>>>> >> on one DSI in some cases. So yes, I would prefer this is done
>>>>>> after
>>>>>> >> both are
>>>>>> >> configured.
>>>>>> >
>>>>>> > I've checked. The power_on is called from
>>>>>> dsi_mgr_bridge_pre_enable()
>>>>>> > when both DSI hosts should be bound.
>>>>>>
>>>>>> DSI being bound is enough? I thought the issue we are trying to
>>>>>> address
>>>>>> is that
>>>>>> we need to have called msm_dsi_host_power_on() for both the hosts so
>>>>>> that both are
>>>>>> put in the known state before requesting the irq.
>>>>>>
>>>>>> OR in other words move the irq_enable() to below location.
>>>>>>
>>>>>> 341 static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
>>>>>> 342 {
>>>>>> ********************************
>>>>>> 364 ret = msm_dsi_host_power_on(host, &phy_shared_timings[id],
>>>>>> is_bonded_dsi, msm_dsi->phy);
>>>>>> 365 if (ret) {
>>>>>> 366 pr_err("%s: power on host %d failed, %d\n",
>>>>>> __func__, id, ret);
>>>>>> 367 goto host_on_fail;
>>>>>> 368 }
>>>>>> 369
>>>>>> 370 if (is_bonded_dsi && msm_dsi1) {
>>>>>> 371 ret = msm_dsi_host_power_on(msm_dsi1->host,
>>>>>> 372 &phy_shared_timings[DSI_1],
>>>>>> is_bonded_dsi, msm_dsi1->phy);
>>>>>> 373 if (ret) {
>>>>>> 374 pr_err("%s: power on host1 failed, %d\n",
>>>>>> 375 __func__,
>>>>>> ret);
>>>>>> 376 goto host1_on_fail;
>>>>>> 377 }
>>>>>> 378 }
>>>>>>
>>>>>> < move the irq enable here >
>>>>>> **********************************
>>>>>
>>>>> Ah, I see your point. What about moving to msm_dsi_host_enable() then?
>>>>
>>>> Yes, I had suggested this a few replies ago. But only at the
>>>> dsi_msgr we know if DSI1 is also done.
>>>> So you can do it right after it in below location?
>>>>
>>>> 427 if (is_dual_dsi && msm_dsi1) {
>>>> 428 ret = msm_dsi_host_enable(msm_dsi1->host);
>>>> 429 if (ret) {
>>>> 430 pr_err("%s: enable host1 failed, %d\n", __func__, ret);
>>>> 431 goto host1_en_fail;
>>>> 432 }
>>>> 433 }
>>>>
>>>> <enable_irq here? >
>>>
>>> If there is DSI1, it was also powered on/programmed at the time of
>>> msm_dsi_host_enable, so enabling IRQs from it should be safe. Do you
>>> see any pitfalls from enabling the irq from that function?
>>
>> Just about symmetry. We will enable_irq() for DSI0 when DSI0 and DSI1
>> are powered on
>> But for DSI1, we will enable it when its powered ON but not enabled.
>> Hence i thought its better this way.
>
> Ah. Then it would be better to call it between power_on() and enable().
> I'll send v3.
V3 sent, moving the enable_irq() out of msm_dsi_host_power_on.
>
>>
>>>
>>>>
>>>>>
>>>>>> >>>> > msm_host->power_on = true;
>>>>>> >>>> > mutex_unlock(&msm_host->dev_mutex);
>>>>>> >>>> >
>>>>>> >>>> > @@ -2439,6 +2440,8 @@ int msm_dsi_host_power_off(struct
>>>>>> mipi_dsi_host
>>>>>> >>>> > *host)
>>>>>> >>>> > goto unlock_ret;
>>>>>> >>>> > }
>>>>>> >>>> >
>>>>>> >>>> > + devm_free_irq(&msm_host->pdev->dev, msm_host->irq,
>>>>>> msm_host);
>>>>>> >>>> > +
>>>>>> >>>> > dsi_ctrl_config(msm_host, false, NULL, NULL);
>>>>>> >>>> >
>>>>>> >>>> > if (msm_host->disp_en_gpio)
>
>
--
With best wishes
Dmitry
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