Re: [PATCH v3 3/7] drm/tegra: Implement .mode_set_base()

[Mark Zhang <nvmarkzhang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 02/18/2013 02:17 PM, Mark Zhang wrote:
> On 02/14/2013 12:05 AM, Thierry Reding wrote:
>> The sequence for replacing the scanout buffer is much shorter than a
>> full mode change operation so implementing this callback considerably
>> speeds up cases where only a new framebuffer is to be scanned out.
>>
>> Signed-off-by: Thierry Reding <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org>
>> ---
>> Changes in v3:
>> - split DC_CMD_STATE_CONTROL writes
>>
>>  drivers/gpu/drm/tegra/dc.c | 31 +++++++++++++++++++++++++++++++
>>  1 file changed, 31 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
>> index 8f97b1c..cc4c85e 100644
>> --- a/drivers/gpu/drm/tegra/dc.c
>> +++ b/drivers/gpu/drm/tegra/dc.c
>> @@ -114,6 +114,27 @@ static int tegra_dc_add_planes(struct drm_device *drm, struct tegra_dc *dc)
>>  	return 0;
>>  }
>>  
>> +static int tegra_dc_set_base(struct tegra_dc *dc, int x, int y,
>> +			     struct tegra_framebuffer *fb)
>> +{
>> +	unsigned long value;
>> +
>> +	tegra_dc_writel(dc, WINDOW_A_SELECT, DC_CMD_DISPLAY_WINDOW_HEADER);
>> +
>> +	value = fb->base.offsets[0] + y * fb->base.pitches[0] +
>> +		x * fb->base.bits_per_pixel / 8;
>> +
>> +	tegra_dc_writel(dc, fb->obj->paddr + value, DC_WINBUF_START_ADDR);
>> +
>> +	value = GENERAL_UPDATE | WIN_A_UPDATE;
>> +	tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
>> +
>> +	value = GENERAL_ACT_REQ | WIN_A_ACT_REQ;
>> +	tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
>> +
>> +	return 0;
>> +}
> 
> Again, what do you think about the "line stride" problem I mentioned:
> 
> http://lists.freedesktop.org/archives/dri-devel/2013-January/033561.html
> 
> Don't get me wrong that I also don't want to add a line stride update
> here because that doesn't make sense. It's just a workaround. But we
> need to find a way to make multi-head page flip working.

Sorry, it's not "multi-head page flip", it should be "multi-head fb
change". For example, if LVDS & HDMI are connected, I can create 4 fbs
for them(every is double-buffered) and call drmModeSetCrtc to switch 2
fbs of LVDS & HDMI to show something.

Mark
> 
> Mark
>> +
>>  static const struct drm_crtc_funcs tegra_crtc_funcs = {
>>  	.set_config = drm_crtc_helper_set_config,
>>  	.destroy = drm_crtc_cleanup,
>> @@ -416,6 +437,15 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc,
>>  	return 0;
>>  }
>>  
>> +static int tegra_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
>> +				    struct drm_framebuffer *old_fb)
>> +{
>> +	struct tegra_framebuffer *fb = to_tegra_fb(crtc->fb);
>> +	struct tegra_dc *dc = to_tegra_dc(crtc);
>> +
>> +	return tegra_dc_set_base(dc, x, y, fb);
>> +}
>> +
>>  static void tegra_crtc_prepare(struct drm_crtc *crtc)
>>  {
>>  	struct tegra_dc *dc = to_tegra_dc(crtc);
>> @@ -495,6 +525,7 @@ static const struct drm_crtc_helper_funcs tegra_crtc_helper_funcs = {
>>  	.disable = tegra_crtc_disable,
>>  	.mode_fixup = tegra_crtc_mode_fixup,
>>  	.mode_set = tegra_crtc_mode_set,
>> +	.mode_set_base = tegra_crtc_mode_set_base,
>>  	.prepare = tegra_crtc_prepare,
>>  	.commit = tegra_crtc_commit,
>>  	.load_lut = tegra_crtc_load_lut,
>>