From: eric@anholt.net (Eric Anholt) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/3] drm/pl111: Use max memory bandwidth for resolution Date: Thu, 22 Feb 2018 12:30:54 -0800 [thread overview] Message-ID: <87k1v4sr5t.fsf@anholt.net> (raw) In-Reply-To: <20180206121854.4407-4-linus.walleij@linaro.org> Linus Walleij <linus.walleij@linaro.org> writes: > We were previously selecting 1024x768 and 32BPP as the default > set-up for the PL111 consumers. > > This does not work on elder systems: the device tree bindings > support a property "max-memory-bandwidth" in bytes/second that > states that if you exceed this the memory bus will saturate. > The result is flickering and unstable images. > > Parse the "max-memory-bandwidth" and respect it when > intializing the driver. On the RealView PB11MP, Versatile and > Integrator/CP we get a nice console as default with this code. > > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > ChangeLog v1->v2: > - Exploit the new .mode_valid() callback we added to the > simple KMS helper. > - Use the hardcoded bits per pixel per variant instead of > trying to be heuristic about this setting for now. > --- > drivers/gpu/drm/pl111/pl111_display.c | 30 ++++++++++++++++++++++++++++++ > drivers/gpu/drm/pl111/pl111_drm.h | 1 + > drivers/gpu/drm/pl111/pl111_drv.c | 6 ++++++ > 3 files changed, 37 insertions(+) > > diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c > index d75923896609..a1ca9e1ffe15 100644 > --- a/drivers/gpu/drm/pl111/pl111_display.c > +++ b/drivers/gpu/drm/pl111/pl111_display.c > + if (bw > priv->memory_bw) { > + DRM_DEBUG("%d x %d @ %d Hz, %d cpp, bw %llu too fast\n", > + mode->hdisplay, mode->vdisplay, mode->clock, cpp, bw); > + > + return MODE_BAD; > + } Oh, hey, on platforms with no memory-bandwidth property, we should make sure not to reject all modes :) -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 832 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20180222/15494b96/attachment.sig>
WARNING: multiple messages have this Message-ID (diff)
From: Eric Anholt <eric@anholt.net> To: Linus Walleij <linus.walleij@linaro.org>, Daniel Vetter <daniel.vetter@intel.com>, Jani Nikula <jani.nikula@linux.intel.com>, Sean Paul <seanpaul@chromium.org>, Peter Ujfalusi <peter.ujfalusi@ti.com>, Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 3/3] drm/pl111: Use max memory bandwidth for resolution Date: Thu, 22 Feb 2018 12:30:54 -0800 [thread overview] Message-ID: <87k1v4sr5t.fsf@anholt.net> (raw) In-Reply-To: <20180206121854.4407-4-linus.walleij@linaro.org> [-- Attachment #1.1: Type: text/plain, Size: 1605 bytes --] Linus Walleij <linus.walleij@linaro.org> writes: > We were previously selecting 1024x768 and 32BPP as the default > set-up for the PL111 consumers. > > This does not work on elder systems: the device tree bindings > support a property "max-memory-bandwidth" in bytes/second that > states that if you exceed this the memory bus will saturate. > The result is flickering and unstable images. > > Parse the "max-memory-bandwidth" and respect it when > intializing the driver. On the RealView PB11MP, Versatile and > Integrator/CP we get a nice console as default with this code. > > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > ChangeLog v1->v2: > - Exploit the new .mode_valid() callback we added to the > simple KMS helper. > - Use the hardcoded bits per pixel per variant instead of > trying to be heuristic about this setting for now. > --- > drivers/gpu/drm/pl111/pl111_display.c | 30 ++++++++++++++++++++++++++++++ > drivers/gpu/drm/pl111/pl111_drm.h | 1 + > drivers/gpu/drm/pl111/pl111_drv.c | 6 ++++++ > 3 files changed, 37 insertions(+) > > diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c > index d75923896609..a1ca9e1ffe15 100644 > --- a/drivers/gpu/drm/pl111/pl111_display.c > +++ b/drivers/gpu/drm/pl111/pl111_display.c > + if (bw > priv->memory_bw) { > + DRM_DEBUG("%d x %d @ %d Hz, %d cpp, bw %llu too fast\n", > + mode->hdisplay, mode->vdisplay, mode->clock, cpp, bw); > + > + return MODE_BAD; > + } Oh, hey, on platforms with no memory-bandwidth property, we should make sure not to reject all modes :) [-- Attachment #1.2: signature.asc --] [-- Type: application/pgp-signature, Size: 832 bytes --] [-- Attachment #2: Type: text/plain, Size: 160 bytes --] _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2018-02-22 20:30 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-02-06 12:18 [PATCH 0/3] Bandwidth limitation on PL111, take 2 Linus Walleij 2018-02-06 12:18 ` Linus Walleij 2018-02-06 12:18 ` [PATCH 1/3] drm: simple_kms_helper: Add mode_valid() callback support Linus Walleij 2018-02-06 12:18 ` Linus Walleij 2018-02-10 17:08 ` Eric Anholt 2018-02-10 17:08 ` Eric Anholt 2018-02-19 9:40 ` Daniel Vetter 2018-02-19 9:40 ` Daniel Vetter 2018-02-06 12:18 ` [PATCH 2/3] drm/pl111: Make the default BPP a per-variant variable Linus Walleij 2018-02-06 12:18 ` Linus Walleij 2018-02-10 17:10 ` Eric Anholt 2018-02-10 17:10 ` Eric Anholt 2018-02-06 12:18 ` [PATCH 3/3] drm/pl111: Use max memory bandwidth for resolution Linus Walleij 2018-02-06 12:18 ` Linus Walleij 2018-02-10 17:14 ` Eric Anholt 2018-02-10 17:14 ` Eric Anholt 2018-02-11 11:05 ` Linus Walleij 2018-02-11 11:05 ` Linus Walleij 2018-02-22 20:30 ` Eric Anholt [this message] 2018-02-22 20:30 ` Eric Anholt
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=87k1v4sr5t.fsf@anholt.net \ --to=eric@anholt.net \ --cc=linux-arm-kernel@lists.infradead.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.