On Mon, Feb 23, 2015 at 09:51:55PM +0100, Bruno Prémont wrote: > As GMUX depends on IO for iGP to be enabled and active, lock the IO at > vgaarb level. This should prevent GPU driver for dGPU to disable IO for > iGP while it tries to own legacy VGA IO. > > This fixes usage of backlight control combined with closed nvidia > driver on some Apple dual-GPU (intel/nvidia) systems. > > On those systems loading nvidia driver disables intel IO decoding, > disabling the gmux backlight controls as a side effect. > Prior to commits moving boot_vga from (optional) efifb to less optional > vgaarb this mis-behavior could be avoided by using right kernel config > (efifb enabled but vgaarb disabled). > > This patch explicitly does not try to trigger vgaarb changes in order > to avoid confusing already running graphics drivers. If IO has been > mis-configured by vgaarb gmux will thus fail to probe. > It is expected to load/probe gmux prior to graphics drivers. > > Fixes: ce027dac592c0ada241ce0f95ae65856828ac450 # nvidia interaction > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=86121 > Reported-by: Petri Hodju <petrihodju@xxxxxxxxx> > Tested-by: Petri Hodju <petrihodju@xxxxxxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: Matthew Garrett <matthew.garrett@xxxxxxxxxx> > Signed-off-by: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx> Hi Bruno, Only a minor nit below. > --- > drivers/platform/x86/apple-gmux.c | 43 ++++++++++++++++++++++++++++++++++++++- > 1 file changed, 42 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c > index b9429fb..22da6a3 100644 > --- a/drivers/platform/x86/apple-gmux.c > +++ b/drivers/platform/x86/apple-gmux.c ... > @@ -475,7 +494,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) > ver_minor = (version >> 16) & 0xff; > ver_release = (version >> 8) & 0xff; > } else { > - pr_info("gmux device not present\n"); > + pr_info("gmux device not present or IO disabled\n"); > ret = -ENODEV; > goto err_release; > } > @@ -483,6 +502,22 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) > pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor, > ver_release, (gmux_data->indexed ? "indexed" : "classic")); > > + /* > + * Apple systems with gmux are EFI based and normally don't use > + * VGA. In addition changing IO+MEM ownership between IGP and dGPU > + * disables IO/MEM used for backlight control on some systems. > + * Lock IO+MEM to GPU with active IO to prevent switch. > + */ > + pdev = gmux_find_pdev(); > + if (pdev && vga_tryget(pdev, > + VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) { > + pr_err("gmux boot_vga IO+MEM vgaarb-locking failed\n"); On this and the above, keep in mind the pr_fmt will already prefix this with KBUILD_MODNAME, the "gmux" is probably redundant. > + ret = -EBUSY; > + goto err_release; > + } else if (pdev) > + pr_info("gmux: locked IO for PCI:%s\n", pci_name(pdev)); The driver uses pr_fmt, so no need to prefix with "gmux:" -- Darren Hart Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
