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

[Liviu Dudau]

Hi Marek,

On Thu, Feb 27, 2025 at 05:58:06PM +0100, Marek Vasut wrote:
> 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.

That doesn't sound right. Can you tell me what GPU firmware are you running
(we are now printing the git sha of the image at boot time).

Best regards,
Liviu

> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Boris Brezillon <boris.brezillon at collabora.com>
> Cc: Conor Dooley <conor+dt at kernel.org>
> Cc: David Airlie <airlied at gmail.com>
> Cc: Fabio Estevam <festevam at gmail.com>
> Cc: Krzysztof Kozlowski <krzk+dt at kernel.org>
> Cc: Liviu Dudau <liviu.dudau at arm.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Maxime Ripard <mripard at kernel.org>
> Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
> Cc: Philipp Zabel <p.zabel at pengutronix.de>
> Cc: Rob Herring <robh at kernel.org>
> Cc: Sascha Hauer <s.hauer at pengutronix.de>
> Cc: Sebastian Reichel <sre at kernel.org>
> Cc: Shawn Guo <shawnguo at kernel.org>
> Cc: Simona Vetter <simona at ffwll.ch>
> Cc: Steven Price <steven.price at arm.com>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: devicetree at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: imx at lists.linux.dev
> Cc: linux-arm-kernel at lists.infradead.org
> ---
>  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
> 

-- 
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| but they're not |
| giving me the   |
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