Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752154Ab1DRVCi (ORCPT ); Mon, 18 Apr 2011 17:02:38 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:53658 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751750Ab1DRVCg (ORCPT ); Mon, 18 Apr 2011 17:02:36 -0400 Date: Mon, 18 Apr 2011 22:03:06 +0100 From: Alan Cox To: Matthew Garrett Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, Matt Turner Subject: Re: [PATCH] drm: Add a driver for kvm emulated Cirrus Message-ID: <20110418220306.7799d850@lxorguk.ukuu.org.uk> In-Reply-To: <1303157094-11425-1-git-send-email-mjg@redhat.com> References: <1303157094-11425-1-git-send-email-mjg@redhat.com> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.0; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1413 Lines: 44 So has this been benchmarked - intuitively I'd agree and expect that a shadowfb driver ought to give best performance. > +/* Map the framebuffer from the card and configure the core */ > +static int cirrus_vram_init(struct cirrus_device *cdev) > +{ > + int ret; > + > + /* BAR 0 is VRAM */ > + cdev->mc.vram_base = pci_resource_start(cdev->ddev->pdev, 0); > + /* We have 4MB of VRAM */ > + cdev->mc.vram_size = 4 * 1024 * 1024; For real hardware at least you should check that the pci resource is at least 4Mb long before doing this, otherwise the resulting progression in the fail case is that you map some other device into user address space, which isn't good! > +static void cirrus_encoder_mode_set(struct drm_encoder *encoder, > + struct drm_display_mode *mode, > + struct drm_display_mode *adjusted_mode) > +{ > + struct drm_device *dev = encoder->dev; > + struct cirrus_device *cdev = dev->dev_private; > + > + unsigned char tmp; > + > + switch (encoder->crtc->fb->bits_per_pixel) { > + case 8: > + tmp = 0x0; > + break; > + case 16: > + /* Enable 16 bit mode */ > + WREG_HDR(0x01); If you switch back from 16 does this not need clearing ? Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/