Re: [RFC 06/14] drm/i915: Disable vlank interrupt for disabling MIPI cmd mode

Singh, Gaurav K
2015-06-16T16:55:01Z

On 5/29/2015 10:53 PM, Daniel Vetter wrote:
> On Fri, May 29, 2015 at 07:14:43PM +0200, Daniel Vetter wrote:
>> On Fri, May 29, 2015 at 04:06:58PM +0530, Gaurav K Singh wrote:
>>> vblank interrupt should be disabled before starting the disable
>>> sequence for MIPI command mode. Otherwise when pipe is disabled
>>> TE interurpt will be still handled and one memory write command
>>> will be sent with pipe disabled. This makes the pipe hw to get
>>> stuck and it doesn't recover in the next enable sequence causing
>>> display blank out.
>>>
>>> Signed-off-by: Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu@intel.com>
>>> Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
>>> ---
>>> drivers/gpu/drm/i915/intel_dsi.c | 14 ++++++++++++++
>>> 1 file changed, 14 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
>>> index 04d8ce0..aeea289 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi.c
>>> +++ b/drivers/gpu/drm/i915/intel_dsi.c
>>> @@ -513,11 +513,25 @@ static void intel_dsi_enable_nop(struct intel_encoder *encoder)
>>>
>>> static void intel_dsi_pre_disable(struct intel_encoder *encoder)
>>> {
>>> + struct drm_device *dev = encoder->base.dev;
>>> struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
>>> + struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
>>> + int pipe = intel_crtc->pipe;
>>> enum port port;
>>>
>>> DRM_DEBUG_KMS("\n");
>>>
>>> + if (is_cmd_mode(intel_dsi)) {
>>> + dev->driver->disable_vblank(dev, pipe);
>>> +
>>> + /*
>>> + * Make sure that the last frame is sent otherwise pipe can get
>>> + * stuck. Currently providing delay time for ~2 vblanks
>>> + * assuming 60fps.
>>> + */
>>> + mdelay(40);
>>> + }
>> Nope. You need to move around the drm_vblank_off suitably, only that
>> function correctly handles all the book-keeping around vblank interrupts.
>> If this doesn't work out because of ordering we need to dig into this and
>> figure out something. Worst case we need to push the drm_vblank_off call
>> into encoder callbacks for everyone. That's something we already discussed
>> but then decided against.
> I seem to be blind, but where exactly is that vblank-driven upload code?
> -Daniel
Hi Daniel,

dev->driver->disable_vblank calls valleyview_disable_vblank which already exists. But I did check with drm_vblank_off, it seems to work fine.

I will float the updated patch shortly.

With regards,
Gaurav

>> -Daniel
>>
>>> +
>>> if (is_vid_mode(intel_dsi)) {
>>> /* Send Shutdown command to the panel in LP mode */
>>> for_each_dsi_port(port, intel_dsi->ports)
>>> --
>>> 1.7.9.5
>>>
>>> _______________________________________________
>>> Intel-gfx mailing list
>>> Intel-gfx@lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> --
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> http://blog.ffwll.ch