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may be a possible solution for LCD flicker

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#1
parvata

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Hi,

Can someone try rolling back the kernel/acer/salsa/drivers/video/msm/lcdc.c lcd driver to an older version where the clock frequency is 58000 and see if the flicker issue with the A1s goes away? I do not have an A1 and also I am busy with other stuff. Hope this will resolve the flicker issue but I am not very sure.

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#2
ccorasaaa

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How i can do it?

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#3
parvata

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How i can do it?

rollback the changes to file, drivers/video/msm/lcdc.c in commit https://github.com/t...ideo/msm/lcdc.c then, compile the kernel only and then flash the generated boot.img using fastboot.

How to flash the kernel only:
- adb reboot bootloader
- cd out/target/product/salsa
- fastboot flash boot boot.img
- fastboot reboot

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#4
alboz83

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rollback the changes to file, drivers/video/msm/lcdc.c in commit https://github.com/t...ideo/msm/lcdc.c then, compile the kernel only and then flash the generated boot.img using fastboot.

How to flash the kernel only:
- adb reboot bootloader
- cd out/target/product/salsa
- fastboot flash boot boot.img
- fastboot reboot

Sorry parvata, i would try to rollback the changes and compile the kernel, but I have never done and i don't know how to make it.
First, i go to your link, i see lcdc.c file, and then?

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#5
parvata

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https://github.com/t...ideo/msm/lcdc.c copy this version of the file into your kernel source and compile the entire source. After that take the boot.img that is present in the out/target/product/salsa and flash it. See if it reduces the flicker. Before flashing this make sure you have a device that shows the flicker. Then flash the new boot.img and see if the flicker goes away.

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#6
alboz83

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https://github.com/t...ideo/msm/lcdc.c copy this version of the file into your kernel source and compile the entire source. After that take the boot.img that is present in the out/target/product/salsa and flash it. See if it reduces the flicker. Before flashing this make sure you have a device that shows the flicker. Then flash the new boot.img and see if the flicker goes away.

Well, i rollback the changes to file and flash the boot.img, but touchscreen don't works.

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#7
parvata

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Well, i rollback the changes to file and flash the boot.img, but touchscreen don't works.


oops...sorry. I have made the change in the file here is the boot image https://sites.google...edirects=0&d=1. Can you try this kernel image? Note that I have tested it on my Liquid E and touch works fine.

Edited by parvata, 14 December 2012 - 05:19 PM.

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#8
alboz83

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No problem!! Ok when i go back at home i try

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#9
ccorasaaa

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Tested it on LiquidE, no flickering!
EDIT: FLICKERING

Edited by ccorasaaa, 15 December 2012 - 12:08 PM.

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#10
alboz83

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oops...sorry. I have made the change in the file here is the boot image https://sites.google...edirects=0&d=1. Can you try this kernel image? Note that I have tested it on my Liquid E and touch works fine.

Flashed, touch works but i have flickering yet. For now seems less then before, but there'is.

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#11
Diljeet

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Thanks guys for trying to get rid of flickering, i am not regularly visiting these forums, please inform me if you some how get the flicker solved.

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@Developers: Thanks for your hard work

#12
alboz83

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Tested it on LiquidE, no flickering!
EDIT: FLICKERING

Well i thought that the problems was A1 only but this change from phone to phone.
@parvata What have you changed in the kernel?
Another question: If I clone and compile liquid-chocolate from github, there are the latest changes or I must to change manually?

Edited by alboz83, 16 December 2012 - 11:15 AM.

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#13
parvata

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Well i thought that the problems was A1 only but this change from phone to phone.
@parvata What have you changed in the kernel?
Another question: If I clone and compile liquid-chocolate from github, there are the latest changes or I must to change manually?

I only changed the lcdx clock frequency to cap out at 58MHz. It was set to 65MHz before. When you checkout the latest source this change is not there. You just make the change manually. Not very hard to change it. Try reducing it further lower and see if the flicker is reduced.

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#14
alboz83

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I only changed the lcdx clock frequency to cap out at 58MHz. It was set to 65MHz before. When you checkout the latest source this change is not there. You just make the change manually. Not very hard to change it. Try reducing it further lower and see if the flicker is reduced.

Ok then i have to change only the number of clock frequency, in these lines?


if (panel_pixclock_freq > 65000000)
/* pm_qos_rate should be in Khz */
pm_qos_rate = panel_pixclock_freq / 1000 ;
else
pm_qos_rate = 65000;

65000000 > 58000000 (or less)
65000 > 58000 (or less)

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#15
parvata

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Ok then i have to change only the number of clock frequency, in these lines?


if (panel_pixclock_freq > 65000000)
/* pm_qos_rate should be in Khz */
pm_qos_rate = panel_pixclock_freq / 1000 ;
else
pm_qos_rate = 65000;

65000000 > 58000000 (or less)
65000 > 58000 (or less)


yes, that is right. Maybe you could also hard code the frequency to 44MHz and see what affect it has. It is a quick and dirty way to find if this frequency is causing the flicker.

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#16
alboz83

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yes, that is right. Maybe you could also hard code the frequency to 44MHz and see what affect it has. It is a quick and dirty way to find if this frequency is causing the flicker.

Ok i tried with frequency to 44, but touchscreen don't works, and i see flickering

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#17
parvata

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Ok i tried with frequency to 44, but touchscreen don't works, and i see flickering

oh ok. The I guess it may be some other change. Unfortunately I do not have an A1 and I cannot suggest any more. But maybe if you give me a history of when you started to see this flicker I can guess which kernel change may have introduced the flicker. I am interested in the cm9 source tree only.

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#18
alboz83

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oh ok. The I guess it may be some other change. Unfortunately I do not have an A1 and I cannot suggest any more. But maybe if you give me a history of when you started to see this flicker I can guess which kernel change may have introduced the flicker. I am interested in the cm9 source tree only.

it's difficult because the flickering, after wake up, sometimes is stranger, sometimes is weaker, without rules. I used ondemand, smartrass2, performance governor, overclock, overvolt, but the flickering is always same.

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