From: yannick Fertre <yannick.fertre@foss.st.com>
To: Raphael GALLAIS-POU - foss <raphael.gallais-pou@foss.st.com>,
"Philippe CORNU - foss" <philippe.cornu@foss.st.com>,
Benjamin Gaignard <benjamin.gaignard@linaro.org>,
David Airlie <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre TORGUE - foss <alexandre.torgue@foss.st.com>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"linux-stm32@st-md-mailman.stormreply.com"
<linux-stm32@st-md-mailman.stormreply.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Yannick FERTRE <yannick.fertre@st.com>,
Philippe CORNU <philippe.cornu@st.com>,
Marek Vasut <marex@denx.de>,
Raphael GALLAIS-POU <raphael.gallais-pou@st.com>
Subject: Re: [PATCH] drm/stm: ltdc: improve pm_runtime to stop clocks
Date: Tue, 6 Jul 2021 17:21:03 +0200 [thread overview]
Message-ID: <40f82de6-5340-347a-ae37-32c0928a5536@foss.st.com> (raw)
In-Reply-To: <20210629115709.16145-1-raphael.gallais-pou@foss.st.com>
Hi Raphaël,
thanks for the patch.
Tested-by: Yannick Fertre <yannick.fertre@foss.st.com>
On 6/29/21 1:58 PM, Raphael GALLAIS-POU - foss wrote:
> Bugzilla ticket: https://intbugzilla.st.com/show_bug.cgi?id=60620
> Gerrit patch: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/208093/
>
> In the LTDC driver, pm_runtime_get_sync was wrongly used and caused the
> LTDC pixel clock to be systematically enabled in the clock summary.
>
> After one simple use of the LTDC by activating and deactivating,
> the clock summary results as below:
>
> ~# cat /sys/kernel/debug/clk/clk_summary | grep ltdc
> ltdc_px 1 1 0 29700000 0 0 50000 N
> ltdc 0 0 0 133250000 0 0 50000 N
>
> By doing so, pm_runtime_get_sync only increments the clock counter when
> the driver was in not active, displaying the right information when the
> LTDC is not in use, resulting of the below clock summary after deactivation
> of the LTDC.
>
> ~# cat /sys/kernel/debug/clk/clk_summary | grep ltdc
> ltdc_px 0 0 0 29700000 0 0 50000 N
> ltdc 0 0 0 133250000 0 0 50000 N
>
> The clocks are activated either by the crtc_set_nofb function or
> by the crtc_atomic_enable function. A check of pm_runtime activity must
> be done before set clocks on. This check must also be done for others
> functions which access registers.
>
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
> ---
> drivers/gpu/drm/stm/ltdc.c | 21 ++++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 08b71248044d..bf9d18023698 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -425,10 +425,17 @@ static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
> {
> struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> struct drm_device *ddev = crtc->dev;
> + int ret;
>
> DRM_DEBUG_DRIVER("\n");
>
> - pm_runtime_get_sync(ddev->dev);
> + if (!pm_runtime_active(ddev->dev)) {
> + ret = pm_runtime_get_sync(ddev->dev);
> + if (ret) {
> + DRM_ERROR("Failed to set mode, cannot get sync\n");
> + return;
> + }
> + }
>
> /* Sets the background color value */
> reg_write(ldev->regs, LTDC_BCCR, BCCR_BCBLACK);
> @@ -783,6 +790,7 @@ static void ltdc_plane_atomic_update(struct drm_plane *plane,
> struct drm_plane_state *newstate = drm_atomic_get_new_plane_state(state,
> plane);
> struct drm_framebuffer *fb = newstate->fb;
> + struct drm_device *ddev = plane->dev;
> u32 lofs = plane->index * LAY_OFS;
> u32 x0 = newstate->crtc_x;
> u32 x1 = newstate->crtc_x + newstate->crtc_w - 1;
> @@ -792,6 +800,11 @@ static void ltdc_plane_atomic_update(struct drm_plane *plane,
> u32 val, pitch_in_bytes, line_length, paddr, ahbp, avbp, bpcr;
> enum ltdc_pix_fmt pf;
>
> + if (!pm_runtime_active(ddev->dev)) {
> + DRM_DEBUG_DRIVER("crtc not activated");
> + return;
> + }
> +
> if (!newstate->crtc || !fb) {
> DRM_DEBUG_DRIVER("fb or crtc NULL");
> return;
> @@ -897,8 +910,14 @@ static void ltdc_plane_atomic_disable(struct drm_plane *plane,
> struct drm_plane_state *oldstate = drm_atomic_get_old_plane_state(state,
> plane);
> struct ltdc_device *ldev = plane_to_ltdc(plane);
> + struct drm_device *ddev = plane->dev;
> u32 lofs = plane->index * LAY_OFS;
>
> + if (!pm_runtime_active(ddev->dev)) {
> + DRM_DEBUG_DRIVER("crtc already deactivated");
> + return;
> + }
> +
> /* disable layer */
> reg_clear(ldev->regs, LTDC_L1CR + lofs, LXCR_LEN);
>
>
prev parent reply other threads:[~2021-07-06 15:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-29 11:58 [PATCH] drm/stm: ltdc: improve pm_runtime to stop clocks Raphael GALLAIS-POU - foss
2021-06-30 0:35 ` Marek Vasut
2021-07-02 9:23 ` Raphael Gallais-Pou
2021-07-02 18:07 ` Marek Vasut
2021-08-17 9:43 ` Raphael Gallais-Pou
2021-08-19 22:22 ` Marek Vasut
2021-07-06 15:21 ` yannick Fertre [this message]
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