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Message-ID: <5614E761.8020706@rock-chips.com> Date: Wed, 07 Oct 2015 17:35:29 +0800 From: Yakir Yang <ykk@...k-chips.com> To: Russell King - ARM Linux <linux@....linux.org.uk> CC: linux-rockchip@...ts.infradead.org, dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, Fabio Estevam <fabio.estevam@...escale.com>, David Airlie <airlied@...ux.ie>, Sascha Hauer <s.hauer@...gutronix.de>, Philipp Zabel <p.zabel@...gutronix.de>, Andy Yan <andy.yan@...k-chips.com>, Jon Nettleton <jon.nettleton@...il.com> Subject: Re: [PATCH 08/12] drm: bridge/dw_hdmi: avoid enabling interface in mode_set On 10/07/2015 05:18 PM, Russell King - ARM Linux wrote: > 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@....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. Hmm... Yeah, it do make some driver logical changes, but I thought that's good, just make a clean on HPD thread, and I do give lots of test on chrome tree about this changes, guess a separate patch would be better. If you don't feel good enough about this, okay, I would give more test on that changes, and send upstream to request comment later. - Yakir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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