From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751461AbeDYHNA (ORCPT ); Wed, 25 Apr 2018 03:13:00 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:62367 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750945AbeDYHM5 (ORCPT ); Wed, 25 Apr 2018 03:12:57 -0400 From: Yannick FERTRE To: Philippe CORNU , Benjamin Gaignard , Vincent ABRIOU , "David Airlie" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" CC: Alexandre TORGUE Subject: Re: [PATCH] drm/stm: ltdc: add mode_valid() Thread-Topic: [PATCH] drm/stm: ltdc: add mode_valid() Thread-Index: AQHT1kDms4rb0CcO1UuIGz3k5PZYoKQQ+5eA Date: Wed, 25 Apr 2018 07:12:47 +0000 Message-ID: References: <20180417114026.8709-1-philippe.cornu@st.com> In-Reply-To: <20180417114026.8709-1-philippe.cornu@st.com> Accept-Language: fr-FR, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.45] Content-Type: text/plain; charset="utf-8" Content-ID: <38A235D74E53E2498001449F85B92BE1@st.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-25_02:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w3P7D4NN006952 Hi Philippe, Reviewed-by: Yannick Fertré On 04/17/2018 01:40 PM, Philippe Cornu wrote: > Add mode_valid() function to filter modes according to available > pll clock values and "preferred" modes. It is particularly > useful for hdmi modes that require precise pixel clocks. > > Note that "preferred" modes are always accepted: > - this is important for panels because panel clock tolerances are > bigger than hdmi ones and there is no reason to not accept them > (the fps may vary a little but it is not a problem). > - the hdmi preferred mode will be accepted too, but userland will > be able to use others hdmi "valid" modes if necessary. > > Signed-off-by: Philippe Cornu > --- > drivers/gpu/drm/stm/ltdc.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c > index 014cef8cef37..616191fe98ae 100644 > --- a/drivers/gpu/drm/stm/ltdc.c > +++ b/drivers/gpu/drm/stm/ltdc.c > @@ -445,6 +445,43 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc, > reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR); > } > > +#define CLK_TOLERANCE_HZ 50 > + > +static enum drm_mode_status > +ltdc_crtc_mode_valid(struct drm_crtc *crtc, > + const struct drm_display_mode *mode) > +{ > + struct ltdc_device *ldev = crtc_to_ltdc(crtc); > + int target = mode->clock * 1000; > + int target_min = target - CLK_TOLERANCE_HZ; > + int target_max = target + CLK_TOLERANCE_HZ; > + int result; > + > + /* > + * Accept all "preferred" modes: > + * - this is important for panels because panel clock tolerances are > + * bigger than hdmi ones and there is no reason to not accept them > + * (the fps may vary a little but it is not a problem). > + * - the hdmi preferred mode will be accepted too, but userland will > + * be able to use others hdmi "valid" modes if necessary. > + */ > + if (mode->type & DRM_MODE_TYPE_PREFERRED) > + return MODE_OK; > + > + result = clk_round_rate(ldev->pixel_clk, target); > + > + DRM_DEBUG_DRIVER("clk rate target %d, available %d\n", target, result); > + > + /* > + * Filter modes according to the clock value, particularly useful for > + * hdmi modes that require precise pixel clocks. > + */ > + if (result < target_min || result > target_max) > + return MODE_CLOCK_RANGE; > + > + return MODE_OK; > +} > + > static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc, > const struct drm_display_mode *mode, > struct drm_display_mode *adjusted_mode) > @@ -559,6 +596,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc, > } > > static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = { > + .mode_valid = ltdc_crtc_mode_valid, > .mode_fixup = ltdc_crtc_mode_fixup, > .mode_set_nofb = ltdc_crtc_mode_set_nofb, > .atomic_flush = ltdc_crtc_atomic_flush, >