On Wed, Sep 11, 2019 at 05:08:45PM +0200, Thomas Zimmermann wrote: > Hi > > Am 10.09.19 um 16:01 schrieb Ville Syrjälä: > > On Mon, Sep 09, 2019 at 04:06:33PM +0200, Thomas Zimmermann wrote: > >> Support for vblank requires VSYNC to signal an interrupt, which is broken > >> on Matrox chipsets. > > > > I don't remember there being anything wrong with the vsync interrupt. > > What makes you think it's broken? > > > >> The workaround that is used here and in other free > >> Matrox drivers is to program <linecomp> to the value of <vdisplay> and > >> enable the VLINE interrupt. This triggers an interrupt at the same time > >> when VSYNC begins. > > > > You're programming it to fire at start of vblank, not start of vsync. > > > >> > >> VLINE uses separate registers for enabling and clearing pending interrupts. > >> No extra syncronization between irq handler and the rest of the driver is > >> required. > >> > >> Signed-off-by: Thomas Zimmermann <[email protected]> > >> --- > >> drivers/gpu/drm/mgag200/mgag200_drv.c | 1 + > >> drivers/gpu/drm/mgag200/mgag200_drv.h | 1 + > >> drivers/gpu/drm/mgag200/mgag200_main.c | 33 ++++++++++++++++++++ > >> drivers/gpu/drm/mgag200/mgag200_mode.c | 42 +++++++++++++++++++++++--- > >> 4 files changed, 73 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c > >> b/drivers/gpu/drm/mgag200/mgag200_drv.c > >> index 4f9df3b93598..cff265973154 100644 > >> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c > >> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c > >> @@ -67,6 +67,7 @@ static struct drm_driver driver = { > >> .driver_features = DRIVER_GEM | DRIVER_MODESET, > >> .load = mgag200_driver_load, > >> .unload = mgag200_driver_unload, > >> + .irq_handler = mgag200_irq_handler, > >> .fops = &mgag200_driver_fops, > >> .name = DRIVER_NAME, > >> .desc = DRIVER_DESC, > >> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.h > >> b/drivers/gpu/drm/mgag200/mgag200_drv.h > >> index 1c93f8dc08c7..88cf256d135f 100644 > >> --- a/drivers/gpu/drm/mgag200/mgag200_drv.h > >> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.h > >> @@ -195,6 +195,7 @@ void mgag200_modeset_fini(struct mga_device *mdev); > >> /* mgag200_main.c */ > >> int mgag200_driver_load(struct drm_device *dev, unsigned long flags); > >> void mgag200_driver_unload(struct drm_device *dev); > >> +irqreturn_t mgag200_irq_handler(int irq, void *arg); > >> > >> /* mgag200_i2c.c */ > >> struct mga_i2c_chan *mgag200_i2c_create(struct drm_device *dev); > >> diff --git a/drivers/gpu/drm/mgag200/mgag200_main.c > >> b/drivers/gpu/drm/mgag200/mgag200_main.c > >> index a9773334dedf..5941607796e8 100644 > >> --- a/drivers/gpu/drm/mgag200/mgag200_main.c > >> +++ b/drivers/gpu/drm/mgag200/mgag200_main.c > >> @@ -10,7 +10,9 @@ > >> > >> #include <drm/drm_crtc_helper.h> > >> #include <drm/drm_gem_framebuffer_helper.h> > >> +#include <drm/drm_irq.h> > >> #include <drm/drm_pci.h> > >> +#include <drm/drm_vblank.h> > >> > >> #include "mgag200_drv.h" > >> > >> @@ -186,10 +188,18 @@ int mgag200_driver_load(struct drm_device *dev, > >> unsigned long flags) > >> } > >> mdev->cursor.pixels_current = NULL; > >> > >> + r = drm_vblank_init(dev, 1); > >> + if (r) > >> + goto err_modeset; > >> + > >> r = drm_fbdev_generic_setup(mdev->dev, 0); > >> if (r) > >> goto err_modeset; > >> > >> + r = drm_irq_install(dev, dev->pdev->irq); > >> + if (r) > >> + goto err_modeset; > >> + > >> return 0; > >> > >> err_modeset: > >> @@ -207,8 +217,31 @@ void mgag200_driver_unload(struct drm_device *dev) > >> > >> if (mdev == NULL) > >> return; > >> + drm_irq_uninstall(dev); > >> mgag200_modeset_fini(mdev); > >> drm_mode_config_cleanup(dev); > >> mgag200_mm_fini(mdev); > >> dev->dev_private = NULL; > >> } > >> + > >> +irqreturn_t mgag200_irq_handler(int irq, void *arg) > >> +{ > >> + struct drm_device *dev = arg; > >> + struct mga_device *mdev = dev->dev_private; > >> + struct drm_crtc *crtc; > >> + u32 status, iclear; > >> + > >> + status = RREG32(0x1e14); > >> + > >> + if (status & 0x00000020) { /* test <vlinepen> */ > >> + drm_for_each_crtc(crtc, dev) { > >> + drm_crtc_handle_vblank(crtc); > >> + } > > > > A bit odd way to write that but as long this driver doesn't support > > crtc2 it should be fine. > > > >> + iclear = RREG32(0x1e18); > >> + iclear |= 0x00000020; /* set <vlineiclr> */ > >> + WREG32(0x1e18, iclear); > >> + return IRQ_HANDLED; > >> + } > >> + > >> + return IRQ_NONE; > >> +}; > >> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c > >> b/drivers/gpu/drm/mgag200/mgag200_mode.c > >> index 5e778b5f1a10..ffe5f15d0a7d 100644 > >> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c > >> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c > >> @@ -905,6 +905,7 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc, > >> const struct drm_framebuffer *fb = crtc->primary->fb; > >> int hdisplay, hsyncstart, hsyncend, htotal; > >> int vdisplay, vsyncstart, vsyncend, vtotal; > >> + int linecomp; > >> int pitch; > >> int option = 0, option2 = 0; > >> int i; > >> @@ -1042,6 +1043,13 @@ static int mga_crtc_mode_set(struct drm_crtc *crtc, > >> vsyncend = mode->vsync_end - 1; > >> vtotal = mode->vtotal - 2; > >> > >> + /* The VSYNC interrupt is broken on Matrox chipsets. We use > >> + * the VLINE interrupt instead. It triggers when the current > >> + * linecomp has been reached. Therefore keep <linecomp> in > >> + * sync with <vdisplay>. > >> + */ > >> + linecomp = vdisplay; > > > > I have an odd recollection that you want vdisplay+1 here if you > > want the interrupt to fire at the correct time. > > I double-checked and found that vdisplay is the value originally used by > this driver, by the fbdev driver and by Xorg's mga driver.
Sure, but what does the hardware actually want? -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
