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@arm.linux.org.uk
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.