On Sun, May 16, 2021 at 06:14:32PM +0100, Emil Velikov wrote: > From: Vivek Das Mohapatra <vivek@xxxxxxxxxxxxx> > > This patch is to do with seamless handover, eg when the sequence is > bootloader → plymouth → desktop. > > It switches the vga arbiter from the "other" GPU to the default one > (intel in this case), so the driver can issue some io(). I don't understand what this commit message is trying to say. > > Signed-off-by: Vivek Das Mohapatra <vivek@xxxxxxxxxxxxx> > Signed-off-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx> > --- > Greetings all, > > This patch has been downstream for a while now yet it seems perfectly > reasonable thing to have in the Linux kernel. > > https://github.com/ValveSoftware/steamos_kernel/commit/5431b5b1999c3d3b5efee817fb3373fbbd473063 > > > drivers/gpu/drm/i915/display/intel_vga.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c > index be333699c515..4f07b5ad5fa0 100644 > --- a/drivers/gpu/drm/i915/display/intel_vga.c > +++ b/drivers/gpu/drm/i915/display/intel_vga.c > @@ -30,12 +30,14 @@ void intel_vga_disable(struct drm_i915_private *dev_priv) > u8 sr1; > > /* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */ > - vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); > - outb(SR01, VGA_SR_INDEX); > - sr1 = inb(VGA_SR_DATA); > - outb(sr1 | 1 << 5, VGA_SR_DATA); > - vga_put(pdev, VGA_RSRC_LEGACY_IO); > - udelay(300); > + if (pdev == vga_default_device()) { > + vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); > + outb(SR01, VGA_SR_INDEX); > + sr1 = inb(VGA_SR_DATA); > + outb(sr1 | 1 << 5, VGA_SR_DATA); > + vga_put(pdev, VGA_RSRC_LEGACY_IO); > + udelay(300); > + } > > intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE); > intel_de_posting_read(dev_priv, vga_reg); > -- > 2.27.0 -- Ville Syrjälä Intel
