On Wed, Oct 07, 2015 at 11:50:53AM +0800, Yakir Yang wrote:
>
>
> On 08/09/2015 12:04 AM, Russell King wrote:
> >On a mode set, DRM makes the following sequence of calls:
> >* for_each_encoder
> >* bridge mode_fixup
> >* encoder mode_fixup
> >* crtc mode_fixup
> >* for_each_encoder
> >* bridge disable
> >* encoder prepare
> >* bridge post_disable
> >* disable unused encoders
> >* crtc prepare
> >* crtc mode_set
> >* for_each_encoder
> >* encoder mode_set
> >* bridge mode_set
> >* crtc commit
> >* for_each_encoder
> >* bridge pre_enable
> >* encoder commit
> >* bridge enable
> >
> >dw_hdmi enables the HDMI output in both the bridge mode_set() and also
> >the bridge enable() step. This is duplicated work - we can avoid the
> >setup in mode_set() and just do it in the enable() stage. This
> >simplifies the code a little.
> >
> >Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
>
> I have noticed that dw_hdmi driver have poweron/poweroff when
> driver detect HPD event in irq thread, that's also duplicated works,
> would you like to collect that changes into this one:
>
> static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
> {
> ......
>
> if (intr_stat & HDMI_IH_PHY_STAT0_HPD) {
> if (phy_int_pol & HDMI_PHY_HPD) {
> dev_dbg(hdmi->dev, "EVENT=plugin\n");
>
> hdmi_modb(hdmi, 0, HDMI_PHY_HPD, HDMI_PHY_POL0);
>
> dw_hdmi_poweron(hdmi); // no need here
> } else {
> dev_dbg(hdmi->dev, "EVENT=plugout\n");
>
> hdmi_modb(hdmi, HDMI_PHY_HPD, HDMI_PHY_HPD,
> HDMI_PHY_POL0);
>
> dw_hdmi_poweroff(hdmi); // no need here
> }
> drm_helper_hpd_irq_event(hdmi->connector.dev);
> }
> ......
> }
I'm very much of the opinion of making small logical changes. This
patch is one small logical change to the DRM-side logic to get rid
of the identified duplication there without touching anything else.
If removing the above calls to dw_hdmi_poweron()/dw_hdmi_poweroff()
were found to cause a regression, then the whole change would end
up being reverted, which would be annoying.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
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