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 at 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.
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
