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 tzimmermann@suse.de
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?