At Fri, 14 Nov 2014 20:39:15 +0100, Takashi Iwai wrote: > > At Fri, 14 Nov 2014 12:29:17 -0500, > Alex Deucher wrote: > > > > On Fri, Nov 14, 2014 at 11:14 AM, Takashi Iwai <tiwai at suse.de> wrote: > > > At Fri, 14 Nov 2014 10:40:08 -0500, > > > Alex Deucher wrote: > > >> > > >> On Fri, Nov 14, 2014 at 5:09 AM, Takashi Iwai <tiwai at suse.de> wrote: > > >> > At Fri, 14 Nov 2014 19:33:00 +1000, > > >> > Dave Airlie wrote: > > >> >> > > >> >> On 14 November 2014 18:12, Takashi Iwai <tiwai at suse.de> wrote: > > >> >> > Hi Alex, > > >> >> > > > >> >> > we've got a few bug reports about the behavior of radeon driver on > > >> >> > machines with Intel+AMD "switchable graphics" (no Muxless). So far, > > >> >> > it seems that the sane only way to make the machine working is to > > >> >> > get > > >> >> > back to the old vgaswitcheroo behavior via radeon.runpm=0. Without > > >> >> > it, radeon GPU gives a spurious output as connected, eventually > > >> >> > crashes GNOME. (Also, from the nature of the switchable graphics, > > >> >> > vgaswitcheroo looks more intuitive to me.) > > >> >> > > >> >> vgaswitcheroo only matters if there is a MUX, the point of it is to > > >> >> drive > > >> >> the MUX. > > >> >> > > >> >> dynamic poweroff makes more sense, switcheroo on/off switch was > > >> >> just a hack. > > >> > > > >> > Well, I find the current form fairly unintuitive, at least, for the > > >> > switchable (not optimus) graphics. > > >> > With dynamic PM, the card is activated on demand. So you may enable > > >> > outputs of both cards at any time, right? > > >> > > > >> > Currently, all outputs from both cards are exposed in Xrandr, > > >> > e.g. LVDS1 DP1, HDMI1, VGA1, LVDS-1-1, HDMI-1-2, DisplayPort-1-2, and > > >> > VGA-1-1. How can user-space know which one should be activated and > > >> > which not, when you can use effectively only a single card? > > >> > > > >> >> > How are such machines supposed to work with the recent system? Is > > >> >> > PX > > >> >> > wrongly detected on them, or something else missing? > > >> >> > > >> >> It sounds like the connector is wrongly detected and that should be > > >> >> what > > >> >> is fixed. > > >> > > > >> > Yeah, that's a problem indeed. In the bug report, both LVDS1 and > > >> > LVDS-1-1 are reported to be connected at the same time while the > > >> > latter doesn't get any real size and position. We didn't trace > > >> > whether this is the culprit of crash of GNOME, but at least, it looks > > >> > fairly weird. > > >> > > > >> > I forgot to give the original bug report: > > >> > http://bugzilla.opensuse.org/show_bug.cgi?id=904417 > > >> > > > >> > and the xrandr output is found at > > >> > http://bugzilla.opensuse.org/show_bug.cgi?id=904417#c18 > > >> > > >> It's not clear to me from the bug report what that problem is. What > > >> exactly is gnome complaining about? > > > > > > It simply crashes by some reason, showing a sad face and complaining > > > something is wrong. (And it's GNOME, not easy to get a proper log > > > like kernel :) > > > Some users complained about blank output, but I'm not sure whether > > > this is the same cause. > > > > > >> The X logs look fine. > > > > > > I couldn't see any errors there, too. So it's just a wild guess, so > > > far... > > > > > >> From the > > >> xrandr output, LVDS1 (connected to the intel) is connected and active. > > >> LVDS-1-1 (connected to the radeon) is connected but not active. That > > >> should be a perfectly reasonable configuration. If LVDS-1-1 is not > > >> active, the radeon kernel driver will power down the GPU until the > > >> user either activates the panel or uses the dGPU as an offscreen > > >> renderer. > > > > > > Note that the xrandr output was taken on icewm or else. So, right, > > > this might be non-issue. But, I guess now that the issue will happen > > > when LVDS-1-1 is activated at the same time with LVDS. GNOME tries to > > > activate all connected outputs at the same time as default. > > > > > >> There are plenty of cases when you may have a secondary GPU with > > >> attached displays that are not active. If gnome barfs on this it > > >> should be fixed in gnome. > > > > > > Yeah, GNOME has definitely a problem about it. At least, it shouldn't > > > crash badly. > > > > > > But, it's still not clear to me how the activation of the radeon GPU > > > is supposed to work in switchable graphics case. For PX or Otpimus, > > > it's clear. But for switchable case, there is no offload rendering. > > > If you enable the output on radeon GPU while Intel output is being > > > used, what's going on? Shouldn't they be handled exclusively, as user > > > expected? > > > > You can still do offload rendering with a switchable system, it just > > happens to also have a mux which you can use or not use. That's how > > it works today. > > > > If you enable the outputs on both gpus, they will both power up the > > display hw on the GPU, but only the signals from the gpu selected by > > the mux will actually make it to the display. > > Yes, that's the problem. The desktop expects that the connected > output can be shown properly at the desired place and size. (GNOME > will try to place all connected outputs from left to right as default, > IIRC.) > But, in this case, it's not informed that some connected outputs are > actually not visible. > > > Does the attached hack help? It basically attempts to determine > > whether the mux is switched to the radeon or not and report > > disconnected or not for the local displays. To handle handle it > > properly, vgaswitcheroo would need to track the signal and ddc/hpd > > muxes and propagate them to the drivers. > > Thanks! I'll provide a test KMP including this patch to reporters to > give a try.
Got a positive feedback, the patch works. Thanks! Takashi
