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Windows 7: Firefox culprit for "reduced leading" in PREFS.JS: FLASH PLUGIN!!!


30 Sep 2012   #1

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 
Firefox culprit for "reduced leading" in PREFS.JS: FLASH PLUGIN!!!

As I continued to try and chase down my "reduced leading" problem whenever I visited certain forum web sites and then closed/re-opened Firefox, I carefully compared my PREFS.JS from a "perfect, working" copy vs. what PREFS.JS looked like right after closing the very first Firefox session after restoring that perfect PREFS.JS.

And very suspiciously, the only thing that had changed in PREFS.JS were two lines that had been added (obviously as a result of that just closed Firefox session, and obviously as a result of something I'd one or site I'd visited in that session). Since I only had visited SevenForums, it obviously had something to do with that site.

Anyway, the two lines which had gotten added to PREFS.JS were:
user_pref("gfx.blacklist.direct2d", 3);
user_pref("gfx.blacklist.layers.direct3d9", 3);
So, I did a little Google searching on these, and guess what I found: a thread in a Mozilla forum which made reference to essentially these same two lines as having been discovered as responsible for an odd "lag" behavior. When that person would delete the two lines, the "lag" behavior would disappear and Firefox performance would return to normal. But when that Firefox session in which behavior was normal would be closed and re-opened, the "lag" behavior would return.

And the only thing that seemed to be different was the appearance of those specific two lines in PREFS.JS. Curious about them, he deleted them before re-launching Firefox, and sure enough the newly launched Firefox session would now behave completely normally!

So he determined that it was THESE two lines which were responsible for his "lag" symptom.

Well, my own research into my own "reduced leading" problem seems to point to the identical two lines somehow re-generating themselves in my PREFS.JS. Even though they are not there initially, after visiting SevenForums and closing Firefox, the two lines are now present in PREFS.JS.

And, if I manually delete those two lines before re-launching Firefox, sure enough the newly launched Firefox session has "normal leading"!!!

So, just as for the other user with the "lag" symptom that keeps re-appearing, so does my "reduced leading" symptom keep re-appearing. And both of our symptoms are 100% related to those two specific lines in PREFS.JS.


Ok... so what did that other user find about the source of those two lines in PREFS.JS and what has to be done in the Firefox session in order for those two lines to re-generate themselves, even if they're not present upon launch?
VISITING A SITE THAT INVOKES THE FLASH PLUGIN PRODUCES THOSE TWO LINES
Yes, apparently that's true!

If I disable the Flash Plugin (v11.4.402.265 on my system) and visit SevenForums, these two lines in PREFS.JS WILL NEVER GET GENERATED, and my "reduced leading" problem totally disappears and "normal leading" remains in effect. I can close and re-open Firefox any number of times, and visit any number of sites, and those two lines WILL NEVER GET GENERATED... and "normal leading" remains in effect.

But all I have to do is re-enable the Flash plugin, and re-launch Firefox (where CNN is my home page, and which I believe makes use of the Flash plugin) and now if I close Firefox sure enough those two lines are re-generated in PREFS.JS and the next launch of Firefox will exhibit the "reduced leading" symptom.


I don't know why this is happening on just this particular machine of mine. I am up-to-date with the Flash plug-in on my other machine as well, and those two lines are NOT PRESENT in PREFS.JS on that other machine. And of course I do NOT have the "reduced leading" problem on that machine.

And yet somehow, on this machine, the enabled Flash plugin for some reason does cause those two critical lines to get re-generated and my "reduced leading" symptom returns:
user_pref("gfx.blacklist.direct2d", 3);
user_pref("gfx.blacklist.layers.direct3d9", 3);
Does any Flash programmer know what these are actually being caused by?
I have an ATI video card on both machines, although one machine has an HD4850 with Catalyst v12.6 drivers and one monitor, and does not produce these two lines. The other "problem" machine has an HD5770 with Catalyst v12.8 and two monitors.

Does anybody know what these two lines mean, what they're for, and why they're generated... apparently not on every Firefox installation?


My System SpecsSystem Spec
.

01 Oct 2012   #2

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 

Ok. I opened a thread on the Firefox support forum and have now had my question answered by truly knowledgeable beings.

The issue with those two lines in PREFS.JS is tied to Firefox's "blacklisting" of certain GPU/driver/OS combinations because they cause instability or crashes in Firefox. This is documented in this article.

And in particular, ATI's Catalyst 12.8 drivers (which support all hardware HD5xxx and higher) ARE BLACKLISTED FOR ALL VERSIONS OF WINDOWS 7!

In other words, those two lines are from Firefox's "blacklist" for Catalyst 12.8.

And this has the identical effect of "turning off hardware acceleration (if the video card supported it)", just as if you'd UN-CHECKED "use hardware acceleration" which is found in Tools -> Options -> Advanced tab -> "use hardware acceleration when available" option.

If you actually do un-check "use hardware acceleration", then you get the following two lines in PREFS.JS:
user_pref("gfx.direct2d.disabled", true);
user_pref("layers.acceleration.disabled", true);
whereas if you do have "use hardware acceleration" checked but say (a) have Flash enabled and visit a site that uses Flash (which obviously must try to take advantage of hardware acceleration), or (b) have Flash disabled but visit a site that "does something fancy" so that again hardware acceleration wants to be taken advantage of, then you get the following two lines in PREFS.JS:
user_pref("gfx.blacklist.direct2d", 3);
user_pref("gfx.blacklist.layers.direct3d9", 3);
But in both cases, the effect is the same: "USE HARDWARE ACCELERATION" IS TURNED OFF.

And apparently it is when hardware acceleration is turned OFF that the "reduced leading" symptom is visible. When hardware acceleration is turned ON, then the "normal leading" appearance occurs.

So it would seem that as long as "basic hardware acceleration" is used (and nothing "fancy" is tried), that "normal leading" appearance is seen. It is only when you actually do something overt which results in the UN-CHECKING (or disabling) of "use hardware acceleration" that the "reduced leading" symptom occurs.


Bottom line: I want to run with "use hardware acceleration" CHECKED, in order to get "normal leading" appearance.

But I have to avoid getting either pair of the above two lines in PREFS.JS. So:

(1) I cannot un-check "use hardware acceleration".

(2) I must run with Flash plugin disabled.

(3) If some web site (even with Flash disabled) tries something "fancy" so that "advanced hardware acceleration" functionality is used which triggers Firefox to invoke "blacklisting" so that the two "blacklisted" lines get generated into PREFS.JS, then I have to manually delete those two lines myself.


I think I now understand it. And its caused by ATI Catalyst 12.8 (8.982) and Firefox, on my machine with the HD5770.

My non-problem machine (which has an HD4850 and therefore can only have Catalyst 12.6, 8.970) is not part of the story, since it's only Catalyst 12.8 which is blacklisted by Firefox because of instability.
My System SpecsSystem Spec
01 Oct 2012   #3

Win 7 Pro x64 SP1, Win 7 Ult x86 SP1
 
 

Thanks for the research and explanation.

Out of curiosity, do you see something different in FF about:config for the setup you have with this issue?
I looked at some PC's and didn't see this issue, but you have explained why...
I looked in about:config and didn't find anything that seemed like it applied to this.
My System SpecsSystem Spec
.


01 Oct 2012   #4

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 

Quote   Quote: Originally Posted by DavidW7ncus View Post
Out of curiosity, do you see something different in FF about:config for the setup you have with this issue?
I looked at some PC's and didn't see this issue, but you have explained why...
I looked in about:config and didn't find anything that seemed like it applied to this.
I'm not sure I follow what you're asking me to look for in about:config?

Even though you might not have the problem on your own machines (probably because you're not running Catalyst 12.8 drivers) I think you can simulate the issue for yourself. If you simply UN-CHECK the "use hardware acceleration when available" option, that should force the creation of the other two lines into PREFS.JS I mentioned above, which are apparently driven specifically by turning that option off.

And with those other two lines in PREFS.JS, I believe you should now seem the same external symptom when visiting SevenForums as if you had Catalyst 12.8 installed which resulted in Firefox automatically "blacklisting" hardware acceleration.


It's really fascinating that the actual display of the text lines of this forum (and others, which use the same "Western (ISO-8859-1)" font as their base) can be different when presented by the video driver (a) with hardware acceleration enabled vs. (b) without hardware acceleration.

Because it's not just the "reduced leading" which is visible. It's also a different horizontal density of characters, and even a different "justification" on the line (so that each paragraph has different words on different lines).

Nevertheless, DFW <-> hardware acceleration ENABLED, while MDR <-> hardware acceleration DISABLED:

My System SpecsSystem Spec
01 Oct 2012   #5

Win 7 Pro x64 SP1, Win 7 Ult x86 SP1
 
 

Quote   Quote: Originally Posted by dsperber View Post
Quote   Quote: Originally Posted by DavidW7ncus View Post
Out of curiosity, do you see something different in FF about:config for the setup you have with this issue?
I looked at some PC's and didn't see this issue, but you have explained why...
I looked in about:config and didn't find anything that seemed like it applied to this.
I'm not sure I follow what you're asking me to look for in about:config?
I just wondered if you see anything in about:config for gfx.blacklist settings.

I asked because you manually edited PREFS.JS, and I see this comment in PREFS.JS

Quote:
# Mozilla User Preferences

/* Do not edit this file.
*
* If you make changes to this file while the application is running,
* the changes will be overwritten when the application exits.
*
* To make a manual change to preferences, you can visit the URL about:config
*/
It's no big deal, i was just curious
My System SpecsSystem Spec
01 Oct 2012   #6

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 

Quote   Quote: Originally Posted by DavidW7ncus View Post
I just wondered if you see anything in about:config for gfx.blacklist settings.

I asked because you manually edited PREFS.JS, and I see this comment in PREFS.JS

/* Do not edit this file.
*
* If you make changes to this file while the application is running,
* the changes will be overwritten when the application exits.
*
* To make a manual change to preferences, you can visit the URL about:config
*/

It's no big deal, i was just curious
Oh, I see.

Well first, I believe about:config is actually a view of PREFS.JS while Firefox is running. When you close Firefox about:config is "saved" into PREFS.JS. That's why the warning in the PREFS.JS file itself.

I first closed Firefox, and then edited PREFS.JS. When Firefox is next opened about:config gets loaded from PREFS.JS, hence accomplishing my purpose.


But to answer your question, while Firefox is open there is no question that the soon-to-be-saved two additional lines in PREFS.JS absolutely have already appeared in about:config, in real time as appropriate.

For example, on the machine running Catalyst 12.8 I started Firefox WITHOUT the two lines being in PREFS.JS, and the Flash plugin disabled. So the session started with "use hardware acceleration" enabled, and "normal leading" as the appearance.

I then enabled the Flash plugin, and went to this SevenForums site... which apparently invokes Flash. As a result, the 12.8 video driver "blacklisting" instantly occurred.

And, if I now look in about:config I see the very two lines which are the soon-to-be additional two lines in PREFS.JS when I close Firefox and PREFS.JS is written from about:config.

My System SpecsSystem Spec
01 Oct 2012   #7

Win 7 Pro x64 SP1, Win 7 Ult x86 SP1
 
 

Thanks for the explanation!
My System SpecsSystem Spec
01 Oct 2012   #8

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 

One further interesting observation, to add to the other facts already presented on this thread.

Turns out if on a machine with Catalyst 12.8 installed with Flash plugin currently disabled, and you do have hardware acceleration enabled, and you go to Tools -> Add-ons, that this very Firefox dialog actually causes its own "crash" (so that the Add-ons page is NOT displayed). Firefox doesn't actually "crash", but the Add-ons page is not completely presented.

In turn, this instantly triggers the creation of the two blacklist lines in PREFS.JS.

So if you then close Firefox and re-launch it, it will start with hardware acceleration disabled (and of course Flash plugin is still disabled as it was before). And now if you go to Tools -> Add-ons, now this will display properly (since hardware acceleration is disabled on the 12.8 driver machine so no FF crash will occur).

In other words, this Add-ons page within Firefox itself is one of the 1% of other assorted random web pages (which are not Flash-based) which will also trigger some issue with hardware acceleration that causes Firefox to again generate the two blacklist lines in PREFS.JS.
My System SpecsSystem Spec
01 Oct 2012   #9

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)
 
 

I've decided not to fight with this any longer. I've got more important things to do.

I've reverted back to Catalyst 12.6 on the problem machine and will just stay there until AMD fixes the driver (hopefully in 12.9) so that Firefox un-blacklists it. I have an HD5770 that worked perfectly with 12.6 before on that machine, and I have no problem staying with 12.6 (just as I'm forced to do on my other machine with the "legacied" HD4850). No problem whatsoever. I'm not a gamer, and the HD5770 is really a "workhorse", not a high-end video card where something in 12.8 might improve performance (e.g. during gaming).

And, now things are 100% again back to normal with Firefox on that HD5770 machine. Hardware acceleration is once again permanently enabled and usable 100% of the time, Flash is enabled, YouTube is usable 100% of the time since Flash in enabled, "normal leading" is in effect on all Forums, Add-ons page in Firefox displays properly, etc. GFX blacklisting will never again be seen and fought with.

100% back to normal, thanks to reversion to Catalyst 12.6.

Case closed.
My System SpecsSystem Spec
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 Firefox culprit for "reduced leading" in PREFS.JS: FLASH PLUGIN!!!




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