[PATCH v2 6/9] drm/panthor: Reset GPU after L2 cache power off

Marek Vasut
2025-03-21T20:07:17Z

This seems necessary on Freescale i.MX95 Mali G310 to reliably resume
from runtime PM suspend. Without this, if only the L2 is powered down
on RPM entry, the GPU gets stuck and does not indicate the firmware is
booted after RPM resume.

Signed-off-by: Marek Vasut <marex@denx.de>
---
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Steven Price <steven.price@arm.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: imx@lists.linux.dev
Cc: linux-arm-kernel@lists.infradead.org
---
V2: No change
---
drivers/gpu/drm/panthor/panthor_gpu.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
index 671049020afaa..0f07ef7d9aea7 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.c
+++ b/drivers/gpu/drm/panthor/panthor_gpu.c
@@ -470,11 +470,12 @@ int panthor_gpu_soft_reset(struct panthor_device *ptdev)
*/
void panthor_gpu_suspend(struct panthor_device *ptdev)
{
- /* On a fast reset, simply power down the L2. */
- if (!ptdev->reset.fast)
- panthor_gpu_soft_reset(ptdev);
- else
- panthor_gpu_power_off(ptdev, L2, 1, 20000);
+ /*
+ * Power off the L2 and soft reset the GPU, that makes
+ * iMX95 Mali G310 resume without firmware boot timeout.
+ */
+ panthor_gpu_power_off(ptdev, L2, 1, 20000);
+ panthor_gpu_soft_reset(ptdev);

panthor_gpu_irq_suspend(&ptdev->gpu->irq);
}
--
2.47.2