Re: [PATCH 2/9] drm/rockchip: vop2: Reset AXI and DCLK to improve robustness

[Philipp Zabel <p.zabel@pengutronix.de>]

On Do, 2026-06-18 at 14:46 +0300, Cristian Ciocaltea wrote:
> On 6/18/26 12:39 PM, Philipp Zabel wrote:
> > On Mi, 2026-06-17 at 21:51 +0300, Cristian Ciocaltea wrote:
> > > Assert the AXI reset in the CRTC disable path, and the VP DCLK reset in
> > > the enable path.
> > > 
> > > These resets are intended to leave the hardware in a clean state for the
> > > next use, helping recover from exceptions such as IOMMU page faults, as
> > > well as to prevent random display output glitches, such as a blank
> > > image, observed when switching modes that also change the color format,
> > > e.g. from RGB to YUV420 and vice versa.
> > > 
> > > For now this seems to affect only the RK3588, hence the resets are
> > > optional and will be provided in the device tree for this SoC only.
> > > 
> > > Co-developed-by: Andy Yan <andy.yan@rock-chips.com>
> > > Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
> > > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> > > ---
> > >  drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 35 ++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/rockchip/rockchip_drm_vop2.h |  4 ++++
> > >  2 files changed, 39 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > index 4cce3e336f5b..2833fb49ad81 100644
> > > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > @@ -17,6 +17,7 @@
> > >  #include <linux/platform_device.h>
> > >  #include <linux/pm_runtime.h>
> > >  #include <linux/regmap.h>
> > > +#include <linux/reset.h>
> > >  #include <linux/swab.h>
> > >  
> > >  #include <drm/drm.h>
> > > @@ -860,6 +861,26 @@ static int vop2_core_clks_prepare_enable(struct vop2 *vop2)
> > >  	return ret;
> > >  }
> > >  
> > > +static void vop2_clk_reset(struct vop2 *vop2, struct reset_control *rstc)
> > 
> > The _clk part of the function name is misleading ...
> 
> Ack.  
> 
> We need to make this clearly distinct from another similarly named function,
> vop2_crtc_reset(), hence I'd propose:
> 
> - vop2_reset_assert_deassert()
> - vop2_reset_cycle()
> - vop2_do_reset()
> 
> Any preference / alternative suggestions?

Or vop2_reset_control_reset(). The three above are equally fine.

regards
Philipp